A038222 - OEIS

A038222

Triangle whose (i,j)-th entry is binomial(i,j)*3^(i-j)*4^j.

1, 3, 4, 9, 24, 16, 27, 108, 144, 64, 81, 432, 864, 768, 256, 243, 1620, 4320, 5760, 3840, 1024, 729, 5832, 19440, 34560, 34560, 18432, 4096, 2187, 20412, 81648, 181440, 241920, 193536, 86016, 16384, 6561, 69984, 326592, 870912, 1451520

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..40.

B. N. Cyvin et al., Isomer enumeration of unbranched catacondensed polygonal systems with pentagons and heptagons, Match, No. 34 (Oct 1996), pp. 109-121.

FORMULA

G.f.: 1/(1 - 3*x - 4*x*y). - Ilya Gutkovskiy, Apr 21 2017

MATHEMATICA

Table[Binomial[i, j]3^(i-j) 4^j, {i, 0, 10}, {j, 0, i}]//Flatten (* Harvey P. Dale, Oct 02 2021 *)

CROSSREFS

Sequence in context: A245455 A296265 A034921 * A038629 A354545 A247087

Adjacent sequences: A038219 A038220 A038221 * A038223 A038224 A038225

KEYWORD

nonn,tabl,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved