A262019 The first of eleven consecutive positive integers the sum of the squares of which is equal to the sum of the squares of five consecutive positive integers.

15, 3575, 637215, 113421575, 20188404015, 3593422493975, 639609015524415, 113846811340852775, 20264092809656270415, 3606894673307475281975, 642006987755920943922015, 114273636925880620542837575, 20340065365818994535681167215, 3620417361478855146730704927575

Offset: 1

Author

Colin Barker, Sep 08 2015

Keywords

• nonn
• easy

Comments

For the first of the corresponding five consecutive positive integers, see A262018.

Examples

			15 is in the sequence because 15^2 + ... + 25^2 = 4510 = 28^2 + ... + 32^2.
		

Links

• Colin Barker, Table of n, a(n) for n = 1..444
• Index entries for linear recurrences with constant coefficients, signature (179,-179,1).

Crossrefs

Cf. A157096, A262017, A262018.

Programs

PARI

Vec(5*x*(5*x^2-178*x-3)/((x-1)*(x^2-178*x+1)) + O(x^20))

Formula

a(n) = 179*a(n-1)-179*a(n-2)+a(n-3) for n>3.

G.f.: 5*x*(5*x^2-178*x-3) / ((x-1)*(x^2-178*x+1)).