OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..746
Index entries for linear recurrences with constant coefficients, signature (1,482,-482,-1,1).
FORMULA
a(n) = a(n-1)+482*a(n-2)-482*a(n-3)-a(n-4)+a(n-5).
G.f.: -x*(x^4+6*x^3-20*x^2+6*x+1) / ((x-1)*(x^2-22*x+1)*(x^2+22*x+1)).
EXAMPLE
469 is in the sequence because it is the 14th heptagonal number and the 13th centered hexagonal number.
MATHEMATICA
LinearRecurrence[{1, 482, -482, -1, 1}, {1, 7, 469, 3367, 226051}, 20] (* Harvey P. Dale, May 17 2019 *)
PROG
(PARI) Vec(-x*(x^4+6*x^3-20*x^2+6*x+1)/((x-1)*(x^2-22*x+1)*(x^2+22*x+1)) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Feb 11 2015
STATUS
approved