A061801 a(n) = (7*6^n - 2)/5.

1, 8, 50, 302, 1814, 10886, 65318, 391910, 2351462, 14108774, 84652646, 507915878, 3047495270, 18284971622, 109709829734, 658258978406, 3949553870438, 23697323222630, 142183939335782, 853103636014694

Offset

0,2

Comments

Sum of n-th row of triangle of powers of 6: 1; 1 6 1; 1 6 36 6 1; 1 6 36 216 36 6 1; ....

Links

Harry J. Smith, Table of n, a(n) for n=0,...,200

Formula

G.f.: (1+x)/(1-6*x)/(1-x) [Zerinvary Lajos, Jan 11 2009]

a(n) = 6*a(n-1) + 2, a(0) = 1. - Philippe Deléham, Feb 23 2014

a(n) = Sum_{k=0..n} A112468(n,k)*7^k. - Philippe Deléham, Feb 23 2014

Example

a(2) = 50 = 1 + 6 + 36 + 6 + 1.
G.f. = 1 + 8*x + 50*x^2 + 302*x^3 + 1814*x^4 + 10886*x^5 + 65318*x^6 + ...

Maple

restart:g:=(1+x)/(1-6*x)/(1-x): gser:=series(g, x=0, 43): seq(coeff(gser, x, n), n=0..30); # Zerinvary Lajos, Jan 11 2009

Prog

(PARI) { for (n=0, 200, write("b061801.txt", n, " ", (7*6^n - 2)/5) ) } \\ Harry J. Smith, Jul 28 2009

Crossrefs

Cf. A057651, A112468, A112739.

Sequence in context: A127745 A243876 A037547 * A240050 A221478 A287812

Adjacent sequences: A061798 A061799 A061800 * A061802 A061803 A061804

Keyword

nonn,easy

Author

Amarnath Murthy, May 28 2001

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Jason Earls, May 28 2001.

Better description from Dean Hickerson, Jun 06 2001

Divided g.f. by x to match the offset. - Philippe Deléham, Feb 23 2014

Status

approved