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A002049
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Prime numbers of measurement.
(Formerly M2633 N1044)
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7
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1, 3, 7, 12, 20, 30, 44, 59, 75, 96, 118, 143, 169, 197, 230, 264, 299, 335, 373, 413, 455, 501, 549, 598, 648, 701, 758, 818, 880, 944, 1009, 1079, 1156, 1236, 1317, 1400, 1485, 1571, 1661, 1752, 1844, 1944, 2048, 2155, 2263, 2379, 2498, 2622, 2749, 2881
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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REFERENCES
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R. K. Guy, Unsolved Problems in Number Theory, E30.
Porubský, Š. On MacMahon's segmented numbers and related sequences. Nieuw Arch. Wisk. (3) 25 (1977), no. 3, 403--408. MR0485763 (58 #5575)
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).
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LINKS
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R. L. Graham and C. B. A. Peck, Problem E1910, Amer. Math. Monthly, 75 (1968), 80-81.
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FORMULA
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Andrews conjectures that a(n) ~ (1/2) n^2 log n / loglog n. - N. J. A. Sloane, Dec 01 2013
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MATHEMATICA
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A002048[anmax_] := (a = {}; Do[AppendTo[a, i], {i, 1, anmax}]; asum = {a[[1]] + a[[2]], a[[2]]}; Do[AppendTo[asum, 0], {i, 3, anmax}]; piv = 3; While[piv <= Length[a], Do[a = DeleteCases[a, asum[[i]]], {i, 1, piv - 2}]; Do[asum[[i]] += a[[piv]], {i, 1, piv}]; piv = piv + 1; ]; a); A002048[200] // Accumulate (* Jean-François Alcover, Oct 05 2016, adapted from R. J. Mathar's Maple code in A002048. *)
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PROG
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(Haskell)
import Data.List ((\\))
a002049 n = a002049_list !! (n-1)
a002049_list = g [1..] [] where
g (x:xs) ys = (last zs) : g (xs \\ zs) (x : ys) where
zs = scanl (+) x ys
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CROSSREFS
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KEYWORD
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nonn,nice
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AUTHOR
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STATUS
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approved
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