OFFSET
1,1
COMMENTS
For the first of the corresponding eight consecutive positive integers, see A262139.
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (7,-7,1).
FORMULA
a(n) = 4*A076708(n+1).
a(n) = 7*a(n-1)-7*a(n-2)+a(n-3) for n>3.
G.f.: 4*x*(x-5) / ((x-1)*(x^2-6*x+1)).
EXAMPLE
20 is in the sequence because 20^2 + ... + 28^2 = 5244 = 22^2 + ... + 29^2.
PROG
(PARI) Vec(4*x*(x-5)/((x-1)*(x^2-6*x+1)) + O(x^40))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Sep 12 2015
STATUS
approved