A038246 Triangle whose (i,j)-th entry is binomial(i,j)*5^(i-j)*4^j.

1, 5, 4, 25, 40, 16, 125, 300, 240, 64, 625, 2000, 2400, 1280, 256, 3125, 12500, 20000, 16000, 6400, 1024, 15625, 75000, 150000, 160000, 96000, 30720, 4096, 78125, 437500, 1050000, 1400000, 1120000, 537600, 143360, 16384, 390625

Offset

0,2

Links

Table of n, a(n) for n=0..36.

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 - 5*x - 4*x*y). - Ilya Gutkovskiy, Apr 21 2017

Crossrefs

Sequence in context: A380314 A180137 A288207 * A176738 A301824 A248255

Adjacent sequences: A038243 A038244 A038245 * A038247 A038248 A038249

Keyword

nonn,tabl,easy

Author

N. J. A. Sloane

Status

approved