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A075406
a(n) is the number of terms in the sum in A075405 (or 0 if no such square exists).
4
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.
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
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