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.

Showing 1-1 of 1 results.

A218213 Number of n-digit primes representable as sums of consecutive squares.

Original entry on oeis.org

1, 4, 13, 30, 69, 187, 519, 1401, 3889, 10861, 31640, 90735
Offset: 1

Views

Author

Martin Renner, Oct 23 2012

Keywords

Comments

There are no common representations of two, three or six squares for n < 13, so
a(n) = A218207(n) + A218209(n) + A218211(n); n < 13.

Crossrefs

Cf. A027861, A027862, A027863, A027864, A027866, A027867, A218207, A218209, A218211.

Programs

  • Mathematica
    nn = 8; nMax = 10^nn; t = Table[0, {nn}]; Do[k = n; s = 0; While[s = s + k^2; s <= nMax, If[PrimeQ[s], t[[Ceiling[Log[10, s]]]]++];  k++], {n, Sqrt[nMax]}]; t (* T. D. Noe, Oct 23 2012 *)

Formula

a(n) = A218214(n) - A218213(n-1).
Showing 1-1 of 1 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.