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A000959
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Lucky numbers.
(Formerly M2616 N1035)
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212
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1, 3, 7, 9, 13, 15, 21, 25, 31, 33, 37, 43, 49, 51, 63, 67, 69, 73, 75, 79, 87, 93, 99, 105, 111, 115, 127, 129, 133, 135, 141, 151, 159, 163, 169, 171, 189, 193, 195, 201, 205, 211, 219, 223, 231, 235, 237, 241, 259, 261, 267, 273, 283, 285, 289, 297, 303
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| An interesting general discussion of the phenomenon of 'random primes' (generalizing the lucky numbers) occurs in Hawkins (1958). Heyde (1978) proves that Hawkins' random primes do not only almost always satisfy the Prime Number Theorem but also the Riemann Hypothesis. - Alf van der Poorten, Jun 27 2002
A145649(a(n)) = 1; complement of A050505. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 15 2008]
Bui and Keating establish an asymptotic formula for the number of k-difference twin primes associated with the Hawkins random sieve, which is a probabilistic model of the Eratosthenes sieve. The formula for k = 1 was obtained by Wunderlich [Acta Arith. 26 (1974), 59 - 81]. We here extend this to k => 2 and generalize it to all l-tuples of Hawkins primes. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Mar 24 2009]
Contribution from Eric Desbiaux (moongerms(AT)wanadoo.fr), Mar 25 2010: (Start)
It appears that a 1's line is formed, as in the Gilbreath's conjecture,
if we use 2(or4),3,5(differ of 7),9,13,15,21,25,...
instead of A000959 1,3,7,9,13,15,21,25,... (End)
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REFERENCES
| M. Gardner, Lucky numbers and 2187, Math. Intellig., 19 (No. 2, 1997), 26-29.
M. Gardner, Gardner's Workout, Chapter 21 "Lucky Numbers and 2187" pp. 149-156 A. K. Peters MA 2002.
V. Gardiner, R. Lazarus, N. Metropolis and S. Ulam, On certain sequences of integers defined by sieves, Math. Mag., 29 (1955), 117-119.
R. K. Guy, Unsolved Problems in Number Theory, C3.
D. Hawkins, The random sieve, Math. Mag. 31 (1958), 1-3.
D. Hawkins and W. E. Briggs, The lucky number theorem. Math. Mag. 31 1958 81-84.
C. C. Heyde, Ann. Probability, 6 (1978), 850-875.
C. S. Ogilvy, Tomorrow's Math. 2nd ed., Oxford Univ. Press, 1972, p. 99.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
D. Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, 114.
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LINKS
| Hugo v. d. Sanden, Table of n, a(n) for n= 1..200000.
H. M. Bui, J. P. Keating, On twin primes associated with the Hawkins random sieve, version 2, Mar 24, 2009. J. Number Theory 119 (2006), 284-296. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Mar 24 2009]
I. Peterson, MathTrek, Martin Gardner's Lucky Numbers
I. Peterson, See also
W. Schneider, Lucky Numbers
T. Sillke, S. M. Ulam's Lucky Numbers
Hugo van der Sanden, Lucky numbers up to 1e8
G. Villemin's Almanach of Numbers, Nombre Chanceux
Eric Weisstein's World of Mathematics, Lucky number.
Wikipedia, Lucky number
Index entries for "core" sequences
Index entries for sequences generated by sieves [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 15 2008]
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FORMULA
| Start with the natural numbers. Delete every 2nd number, leaving 1 3 5 7 ...; the 2nd number remaining is 3, so delete every 3rd number, leaving 1 3 7 9 13 15 ...; now delete every 7th number, leaving 1 3 7 9 13 ...; now delete every 9th number; etc.
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MAPLE
| ## luckynumbers(n) returns all lucky numbers from 1 to n. ## Try n=10^5 just for fun. luckynumbers:=proc(L) local k, Lnext, Lprev; Lprev:=[$1..n]; for k from 1 do if k=1 or k=2 then Lnext:= map(w-> Lprev[w], remove(z -> z mod Lprev[2] = 0, [$1..nops(Lprev)])); if nops(Lnext)=nops(Lprev) then break fi; Lprev:=Lnext; else Lnext:= map(w-> Lprev[w], remove(z -> z mod Lprev[k] = 0, [$1..nops(Lprev)])); if nops(Lnext)=nops(Lprev) then break fi; Lprev:=Lnext; fi; od; return Lnext; end: - Walter A. Kehowski (wkehowski(AT)cox.net), Jun 05 2008
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MATHEMATICA
| t = 2Range@200 - 1; f[n_] := Block[{k = t[[n]]}, t = Delete[t, Table[{k}, {k, k, Length@t, k}]]]; Do[f@n, {n, 2, 30}]; t (from Robert G. Wilson v (rgwv(at)rgwv.com), May 09 2006)
nn=10^6; t=Range[1, nn, 2]; sieve[n_]:=Module[{k=t[[n]]}, t=Delete[t, Table[{i}, {i, k, Length[t], k}]]]; n = 1; While[t[[n]]<Length[t], n++; sieve[n]]; t
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PROG
| (Haskell)
a000959 n = a000959_list !! (n-1)
a000959_list = 1 : sieve 2 [1, 3..] where
sieve k xs = z : sieve (k + 1) (lucky xs) where
z = xs !! (k - 1 )
lucky ws = us ++ lucky vs where
(us, _:vs) = splitAt (z - 1) ws
-- Reinhard Zumkeller, Dec 05 2011
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CROSSREFS
| Cf. A137164-A137185.
Cf. A039672, A045954.
Sequence in context: A073671 A172367 A024901 * A204085 A120226 A137310
Adjacent sequences: A000956 A000957 A000958 * A000960 A000961 A000962
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KEYWORD
| nonn,easy,nice,core
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com). Entry updated Mar 07 2008
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