OFFSET
1,1
COMMENTS
For the first of the corresponding nine consecutive positive integers, see A262140.
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) = 7*a(n-1)-7*a(n-2)+a(n-3) for n>3.
G.f.: -x*(x^2-9*x+22) / ((x-1)*(x^2-6*x+1)).
a(n) = (-14+3*(3-2*sqrt(2))^(1+n)+3*(3+2*sqrt(2))^(1+n))/4. - Colin Barker, Mar 05 2016
EXAMPLE
22 is in the sequence because 22^2 + ... + 29^2 = 5244 = 20^2 + ... + 28^2.
MATHEMATICA
LinearRecurrence[{7, -7, 1}, {22, 145, 862}, 30] (* Harvey P. Dale, Apr 19 2016 *)
PROG
(PARI) Vec(-x*(x^2-9*x+22)/((x-1)*(x^2-6*x+1)) + O(x^40))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Sep 12 2015
STATUS
approved