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

1,1

Comments

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

Links

Colin Barker, Table of n, a(n) for n = 1..444

Index entries for linear recurrences with constant coefficients, signature (179,-179,1).

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)).

Example

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

Prog

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

Crossrefs

Cf. A157096, A262017, A262018.

Sequence in context: A145189 A182283 A194479 * A153832 A198524 A208463

Adjacent sequences: A262016 A262017 A262018 * A262020 A262021 A262022

Keyword

nonn,easy

Author

Colin Barker, Sep 08 2015

Status

approved