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Search: id:A112877
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A112877 Zeros in Cald's sequence: positions n such that A006509(n) = 0. +0
5
117, 199, 381, 427, 521, 721, 1151, 1997, 3625, 6607, 12269, 23209, 41133, 75441, 141209, 266969, 507701, 968373 (list; graph; listen)
OFFSET

1,1

EXAMPLE

A006509(117) = 0 and A006509(k) > 0 for k < 117, so a(1) = 117.

MATHEMATICA

a[1] = 1; a[n_] := a[n] = Block[{b = a[n - 1], p = Prime[n - 1]}, If[ b - p > 0 && Position[t, b - p] == {}, b - p, If[ Position[t, b + p] == {}, b + p, 0]]]; t = {1}; Do[ AppendTo[t, a[n]], {n, 2, 270000}]; Flatten[ Position[t, 0]] (* Robert G. Wilson v *)

CROSSREFS

Cf. A006509, A112878, A117128, A117129.

Sequence in context: A015706 A095625 A109023 this_sequence A064180 A050245 A031174

Adjacent sequences: A112874 A112875 A112876 this_sequence A112878 A112879 A112880

KEYWORD

nonn

AUTHOR

Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Oct 24 2005

EXTENSIONS

a(15) and a(16) from Robert G. Wilson v (rgwv(at)rgwv.com), Oct 29 2005

a(17) and a(18) from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jan 01 2006

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.


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