login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A288835
a(n) = (1/2!)*3^n*(n+3)*(n).
3
6, 45, 243, 1134, 4860, 19683, 76545, 288684, 1062882, 3838185, 13640319, 47829690, 165809592, 569173311, 1937102445, 6543101592, 21953827710, 73222472421, 242912646603, 801960412230, 2636009007156, 8629791392475, 28148810469273, 91507169819844
OFFSET
1,1
FORMULA
O.g.f.: z*3^1*(2-3*z)/(1-3*z)^3.
a(n) = A287768(n+3,4).
MATHEMATICA
Table[(1/2!)*3^n*(n + 3) n, {n, 24}] (* Michael De Vlieger, Jun 23 2017 *)
LinearRecurrence[{9, -27, 27}, {6, 45, 243}, 30] (* Harvey P. Dale, Apr 04 2020 *)
CROSSREFS
Column k=4 of A287768.
Sequence in context: A122096 A302709 A054563 * A162230 A258350 A258623
KEYWORD
nonn
AUTHOR
STATUS
approved