A274073 a(n) = 6^n-(-1)^n.

0, 7, 35, 217, 1295, 7777, 46655, 279937, 1679615, 10077697, 60466175, 362797057, 2176782335, 13060694017, 78364164095, 470184984577, 2821109907455, 16926659444737, 101559956668415, 609359740010497, 3656158440062975, 21936950640377857, 131621703842267135

Offset: 0

Author

Colin Barker, Jun 09 2016

Keywords

• nonn
• easy

Links

• Colin Barker, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (5,6).

Crossrefs

Cf. A015540.

Sequences of the type k^n-(-1)^n: A062157 (k=0), A010673 (k=1), A062510 (k=2), A105723 (k=3), A247281 (k=4), A274072 (k=5), this sequence (k=6).

Programs

PARI

concat(0, Vec(7*x/((1+x)*(1-6*x)) + O(x^30)))

Formula

O.g.f.: 7*x/((1+x)*(1-6*x)).

E.g.f.: exp(6*x) - exp(-x).

a(n) = 5*a(n-1) + 6*a(n-2) for n>1.

a(n) = 7*A015540(n).