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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.
3
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.
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
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Sep 08 2015
STATUS
approved