login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A229019 Minimal position at which the sequence defined in the same way as A159559 but with initial term prime(n) merges with A159559; a(n)=0 if there is no such position. 10
2, 11, 47, 47, 47, 683, 683, 683, 683, 683, 683, 683, 683, 683, 683, 683, 683, 1117, 1117, 1117, 1117, 1117, 1117, 1117, 1117, 1117, 1117, 1117, 6257, 6257, 6257, 6257, 6257, 6257, 6257, 6257, 390703, 390703, 390703, 390703, 390703, 390703, 390703, 390703 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,1
COMMENTS
All positive terms of the sequence are prime.
Conjecture: all terms are positive.
LINKS
EXAMPLE
For n>=2, denote by A_n the sequence defined in the same way as A159559 but with initial term A_n(2)=prime(n). In case n=2 A_2(2)=3, hence A_2 = A159559, and so a(2)=2. Suppose n=3. Then A_3(2)=5 and by the definition of A159559 we have A_3(3)=7, A_3(4)=8, A_3(5)=11, A_3(6)=12, A_3(7)=13, A_3(8)=14, A_3(9)=15, A_3(10)=16, A_3(11)=17. Since A159559(11) is also 17, then, beginning with 11, A_3 merges with A159559 and a(3)=11. - Vladimir Shevelev, Sep 11 2016.
MAPLE
b:= proc(n, p) option remember; local m;
if n=2 then p
else for m from b(n-1, p)+1 while isprime(m) xor isprime(n)
do od; m
fi
end:
a:= proc(n) option remember; local k;
for k from 2 while b(k, 3)<>b(k, ithprime(n)) do od; k
end:
seq(a(n), n=2..20); # Alois P. Heinz, Sep 15 2013
MATHEMATICA
f[n_, r_] := Block[{a}, a[2] = n; a[x_] := a[x] = If[PrimeQ@ x, NextPrime@ a[x - 1], NestWhile[# + 1 &, a[x - 1] + 1, PrimeQ@ # &]]; Map[a, Range[2, r]]]; nn = 10^4; t = f[3, nn]; Table[1 + First@ Flatten@ Position[BitXor[t, f[Prime@ n, nn]], 0], {n, 2, 37}] (* Michael De Vlieger, Sep 13 2016, after Peter J. C. Moses at A159559 *)
CROSSREFS
Sequence in context: A042927 A292533 A140305 * A142346 A106980 A089682
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Sep 11 2013
EXTENSIONS
More terms from Alois P. Heinz, Sep 15 2013
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 21 06:16 EST 2024. Contains 370219 sequences. (Running on oeis4.)