A180347 The number of n-digit numbers requiring 4 nonzero squares in their representation as sum of squares.

1, 14, 150, 1500, 14999, 150000, 1499999, 15000000, 149999998, 1500000001, 14999999999, 149999999999, 1500000000001, 14999999999999, 149999999999999, 1500000000000001, 14999999999999998, 149999999999999999, 1500000000000000003, 14999999999999999996

Offset: 1

Author

Martin Renner, Jan 18 2011

Keywords

• nonn
• base

Comments

A049415(n) + A180426(n) + A180429(n) + a(n) = A052268(n).

Links

• Eric W. Weisstein: MathWorld : Lagrange's Four-Square Theorem.
• Eric W. Weisstein: MathWorld: Sum of Squares Function.

Crossrefs

Cf. A004215, A167615.

Cf. A049415, A052268, A180426, A180429.

Formula

a(n) = A167615(n)-A167615(n-1).