login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A038215 Triangle whose (i,j)-th entry is binomial(i,j)*2^(i-j)*9^j. 0
1, 2, 9, 4, 36, 81, 8, 108, 486, 729, 16, 288, 1944, 5832, 6561, 32, 720, 6480, 29160, 65610, 59049, 64, 1728, 19440, 116640, 393660, 708588, 531441, 128, 4032, 54432, 408240, 1837080, 4960116, 7440174, 4782969, 256, 9216, 145152 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

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

LINKS

Table of n, a(n) for n=0..38.

MATHEMATICA

Table[Binomial[x, y]2^(x-y) 9^y, {x, 0, 10}, {y, 0, x}]//Flatten (* Harvey P. Dale, Jun 17 2017 *)

CROSSREFS

Sequence in context: A054789 A002508 A249596 * A264110 A119019 A268204

Adjacent sequences:  A038212 A038213 A038214 * A038216 A038217 A038218

KEYWORD

nonn,tabl,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 30 17:21 EDT 2021. Contains 346359 sequences. (Running on oeis4.)