A180426 The number of n-digit numbers requiring 2 nonzero squares in their representation as sum of squares.

3, 30, 265, 2351, 21062, 191630, 1766955, 16465551, 154749588, 1464326721, 13932672360, 133165432342, 1277568139729, 12295904124627, 118665023703067, 1147922359531155

Offset

1,1

Comments

A049415(n) + a(n) + A180429(n) + A180347(n) = A052268(n)

Links

Table of n, a(n) for n=1..16.

Eric W. Weisstein: MathWorld -- Lagrange's Four-Square Theorem.

Eric W. Weisstein: MathWorld -- Sum of Squares Function.

Formula

a(n) = A180416(n)-A180416(n-1) for n>1.

Crossrefs

Cf. A000404, A180416.

Sequence in context: A178015 A120689 A359614 * A246246 A136896 A121085

Adjacent sequences: A180423 A180424 A180425 * A180427 A180428 A180429

Keyword

nonn,more,base

Author

Martin Renner, Jan 19 2011

Extensions

a(5)-a(8) from Alois P. Heinz, Jan 20 2011

a(9)-a(10) from Donovan Johnson, Jul 01 2011

a(10) corrected and a(11)-a(16) added by Hiroaki Yamanouchi, Aug 30 2014

Status

approved