A127397 a(0)=0; a(n) = smallest positive integer not occurring earlier in the sequence such that a(n-1)+a(n) = j^k, j = any positive integer, k = any integer >= 2.

0, 1, 3, 5, 4, 12, 13, 14, 2, 6, 10, 15, 17, 8, 19, 30, 34, 47, 53, 11, 16, 9, 7, 18, 31, 33, 48, 52, 29, 20, 44, 37, 27, 22, 42, 39, 25, 24, 40, 41, 23, 26, 38, 43, 21, 28, 36, 45, 55, 66, 59, 62, 63, 58, 67, 54, 46, 35, 65, 56, 69, 75, 50, 71, 57, 64, 61, 60, 68, 32, 49, 51, 70

Offset: 0

Author

Leroy Quet, Jan 12 2007

Keywords

• nonn
• look

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A001597, A034175, A127398.

Programs

Mathematica

f[n_] := n == 1 || GCD @@ Last /@ FactorInteger[n] > 1;g[l_List] := Block[{k = 1},While[MemberQ[l, k] || ! f[k + l[[ -1]]], k++ ];Append[l, k]];Nest[g, {0}, 73] (* Ray Chandler, Jan 22 2007 *)

Extensions

Extended by Ray Chandler, Jan 22 2007