A075406 a(n) is the number of terms in the sum in A075405 (or 0 if no such square exists).

24, 0, 2, 0, 0, 0, 23, 0, 24, 0, 22898, 0, 96, 0, 97, 0, 23, 11, 0, 2, 96, 59, 0, 0, 24, 0, 33, 50, 0, 169, 0, 578, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0, 122, 0, 96, 0, 0, 3479, 0, 0, 2075, 0, 33, 0, 0, 0, 242, 218, 0, 50, 0, 0, 0, 0, 0, 122, 36481, 0, 24, 0, 0, 0, 0, 0, 0, 194, 0, 0, 0, 50, 0, 0, 0, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,1

Comments

Note that a(n) is either 0 or a number in A001032.

References

See A180422.

Links

Table of n, a(n) for n=1..100.

Example

a(1) = 25 because the sum 1^2+...+24^2 consists of 25 terms, see A075404.

Mathematica

s[n_, k_]:=Module[{m=n+k-1}, (m(m+1)(2m+1)-n(n-1)(2n-1))/6]; mx=40000; Table[k=2; While[k<mx && !IntegerQ[Sqrt[s[n, k]]], k++]; If[k==mx, 0, k], {n, 100}]

Crossrefs

Cf. A000330, A075404, A075405.

Sequence in context: A368027 A357967 A353227 * A075404 A356304 A308234

Adjacent sequences: A075403 A075404 A075405 * A075407 A075408 A075409

Keyword

nonn

Author

Zak Seidov, Sep 13 2002

Extensions

Corrected and extended by Lior Manor Sep 19 2002

Corrected and edited by T. D. Noe, Jan 21 2011

Status

approved