A228004 Prime powers p^m with m >= 2 which are not the sum of consecutive cubes.

4, 16, 25, 32, 49, 81, 121, 128, 169, 243, 256, 289, 361, 529, 625, 841, 961, 1024, 1369, 1681, 1849, 2048, 2187, 2209, 2401, 2809, 3125, 3481, 3721, 4489, 5041, 5329, 6241, 6561, 6889, 7921, 8192, 9409, 10201, 10609, 11449, 11881, 12769, 14641, 16129

Offset

1,1

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10137

K. S. Brown, Sum of Consecutive Nth Powers Equals an Nth Power

G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 97

Example

9 is not in the sequence since it is equal to 1^3 + 2^3.

Prog

(Magma) lst:=[]; r:=26; c:=r^3; for n in [2..r] do for m in [n-1..0 by -1] do s:=((n^2+n)^2-(m^2+m)^2)/4; if s gt c then break; end if; if not s in lst then Append(~lst, s); end if; end for; end for; lst:=Sort(lst); [p: p in [2..c] | not IsPrime(p) and IsPrimePower(p) and not p in lst];

Crossrefs

Cf. A025475, A217843.

Sequence in context: A239522 A281990 A103052 * A269157 A343726 A202303

Adjacent sequences: A228001 A228002 A228003 * A228005 A228006 A228007

Keyword

nonn

Author

Arkadiusz Wesolowski, Aug 07 2013

Status

approved