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A180426 The number of n-digit numbers requiring 2 nonzero squares in their representation as sum of squares. 3
3, 30, 265, 2351, 21062, 191630, 1766955, 16465551, 154749588, 1464326721, 13932672360, 133165432342, 1277568139729, 12295904124627, 118665023703067, 1147922359531155 (list; graph; refs; listen; history; text; internal format)
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: A043030 A178015 A120689 * 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

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Last modified March 22 12:23 EDT 2019. Contains 321421 sequences. (Running on oeis4.)