%I A112877
%S A112877 117,199,381,427,521,721,1151,1997,3625,6607,12269,23209,41133,75441,
%T A112877 141209,266969,507701,968373
%N A112877 Zeros in Cald's sequence: positions n such that A006509(n) = 0.
%e A112877 A006509(117) = 0 and A006509(k) > 0 for k < 117, so a(1) = 117.
%t A112877 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 *)
%Y A112877 Cf. A006509, A112878, A117128, A117129.
%Y A112877 Sequence in context: A015706 A095625 A109023 this_sequence A064180 A050245 
               A031174
%Y A112877 Adjacent sequences: A112874 A112875 A112876 this_sequence A112878 A112879 
               A112880
%K A112877 nonn
%O A112877 1,1
%A A112877 Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Oct 24 2005
%E A112877 a(15) and a(16) from Robert G. Wilson v (rgwv(at)rgwv.com), Oct 29 2005
%E A112877 a(17) and a(18) from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), 
               Jan 01 2006