

A112877


Zeros in Cald's sequence: positions n such that A006509(n) = 0.


4



117, 199, 381, 427, 521, 721, 1151, 1997, 3625, 6607, 12269, 23209, 41133, 75441, 141209, 266969, 507701, 968373, 1851971, 3549473, 6817481, 13115259, 25267949, 48750929, 94173137, 182122379
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..26.


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: A272389 A201021 A187990 * A064180 A050245 A031174
Adjacent sequences: A112874 A112875 A112876 * A112878 A112879 A112880


KEYWORD

nonn


AUTHOR

Klaus Brockhaus, Oct 24 2005


EXTENSIONS

a(15) and a(16) from Robert G. Wilson v, Oct 29 2005
a(17) and a(18) from Klaus Brockhaus, Jan 01 2006
a(19)a(26) from Donovan Johnson, Feb 18 2010


STATUS

approved



