OFFSET
1,1
LINKS
Colin Barker, Table of n, a(n) for n = 1..158
Index entries for linear recurrences with constant coefficients, signature (2079363,-2079363,1).
FORMULA
G.f.: -171*x*(1443*x+1) / ((x-1)*(x^2-2079362*x+1)).
EXAMPLE
171 is in the sequence because 171 is the 18th triangular number, and 2*171 is the 12th heptagonal number.
MATHEMATICA
LinearRecurrence[{2079363, -2079363, 1}, {171, 355817826, 739874066553765}, 20] (* Vincenzo Librandi, Jun 20 2015 *)
PROG
(PARI) Vec(-171*x*(1443*x+1) / ((x-1)*(x^2-2079362*x+1)) + O(x^20))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Jun 19 2015
STATUS
approved