A278342 Zero terms of A278341.
1, 2, 3, 4, 5, 7, 32, 52, 55, 56, 58, 61, 64, 66, 72, 80, 86, 88, 89, 94, 101, 103, 108, 109, 128, 130, 131, 161, 173, 187, 193, 194, 213, 214, 224, 244, 253, 260, 270, 292, 304, 314, 323, 334, 344, 348, 349, 365, 370, 373, 388, 404, 424, 454, 470, 478, 482
Offset: 1
Examples
A278341(1,2,3,4,5,7)=0, so a(1)=1, a(2)=2,...,a(5)=5, and a(6)=7.
a(7)=32 is because 32 cannot be decomposited into the sum of two terms in A274987={3, 5, 7, 11, 13, 17, 23, 31, 37, 53, 59, 61, 73, 79, 83, 89, 101, 103, 109...}.
Links
- Lei Zhou, Table of n, a(n) for n = 1..208
Programs
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Mathematica
p = 3; sp = {p}; m = 0; Table[ While[m++; l = Length[sp]; While[sp[[l]] < m, While[p = NextPrime[p]; cp = 2*3^(Floor[Log[3, 2*p - 1]]) - p; ! PrimeQ[cp]]; AppendTo[sp, p]; l++]; c = 2 - Mod[m + 1, 2]; ct = 0; Do[If[MemberQ[sp, m - c*sp[[i]]], If[Abs[Floor[Log[3, 2*sp[[i]] - 1]] - Floor[Log[3, 2*(m - c*sp[[i]]) - 1]]] <= 1, If[c == 1, If[(2*sp[[i]]) <= m, ct++], ct++]]], {i, 1, l}]; ct > 0]; m, {n, 1, 208}]
Comments