cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A048155 a(n)=Sum{T(n,k): k=1,2,...,n}, array T as in A048154.

Original entry on oeis.org

0, 1, 3, 4, 10, 15, 21, 16, 27, 45, 55, 60, 78, 91, 105, 96, 136, 135, 171, 180, 210, 231, 253, 240, 250, 325, 243, 364, 406, 435, 465, 384, 528, 561, 595, 540, 666, 703, 741, 720, 820, 861, 903, 924, 945, 1035, 1081, 1056, 1029
Offset: 1

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Examples

			a(3) = 3 since (1^3 mod 3) + (2^3 mod 3) + (3^3 mod 3) = (1 mod 3) + (8 mod 3) + (27 mod 3) = 1 + 2 + 0 = 3.
		

Crossrefs

Cf. A048154.

Programs

  • Mathematica
    Table[Sum[Mod[k^3, n], {k, n}], {n, 50}] (* or *)
    Table[Sum[k (1 - Floor[k^3/n] + Floor[(k^3 - 1)/n]), {k, n}], {n, 50}] (* Michael De Vlieger, Jun 26 2016 *)

Formula

a(n) = Sum_{k=1..n} k*(1-floor(k^3/n)+floor((k^3 -1)/n)). - Anthony Browne, Jun 26 2016