OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..416
Index entries for linear recurrences with constant coefficients, signature (254,-1).
FORMULA
a(n) = 254*a(n-1) - a(n-2).
G.f.: -x*(x-1) / (x^2 - 254*x + 1).
a(n) = (1/8)*T(2*n-1, 8), where T(n,x) denotes the n-th Chebyshev polynomial of the first kind. - Peter Bala, Jul 08 2022
EXAMPLE
253 is in the sequence because it is the 22nd triangular number and the 9th centered heptagonal number.
MATHEMATICA
LinearRecurrence[{254, -1}, {1, 253}, 20] (* Harvey P. Dale, May 17 2017 *)
PROG
(PARI) Vec(-x*(x-1)/(x^2-254*x+1) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Jan 17 2015
STATUS
approved