

A180425


Number of positive integers below 10^n requiring 3 positive squares in their representation as sum of squares.


4



2, 42, 505, 5586, 59308, 616995, 6347878, 64875490, 660104281, 6695709182, 67762820595, 684596704482, 6907026402474, 69611115440126, 700946070114283, 7053023642205904
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..16.
Eric W. Weisstein, MathWorld  Lagrange's FourSquare Theorem.
Eric W. Weisstein, MathWorld  Sum of Squares Function.


FORMULA

a(n) = #{k: A000419(k) < 10^n}.
A049416(n) + A180416(n) + a(n) + A167615(n) = A002283(n).


CROSSREFS

Cf. A000419, A049416, A180416, A167615, A002283.
Sequence in context: A070808 A229474 A157056 * A140170 A318247 A038396
Adjacent sequences: A180422 A180423 A180424 * A180426 A180427 A180428


KEYWORD

nonn,more


AUTHOR

Martin Renner, Jan 19 2011


EXTENSIONS

a(6)=616995 by Lars Blomberg, May 03 2011
a(7)a(10) from Donovan Johnson, Jul 01 2011
a(10) corrected and a(11)a(16) from Hiroaki Yamanouchi, Jul 13 2014


STATUS

approved



