|
|
A062030
|
|
Group even numbers into (2,4), (6,8,10,12), (14,16,18,20,22,24), ...; a(n) = product of n-th group.
|
|
5
|
|
|
8, 5760, 42577920, 1300252262400, 111644006842368000, 21695920874860629196800, 8291067715225260172247040000, 5644260808699395278689265516544000, 6360332664265371581768550654463180800000, 11209384544297234954537967755979151481241600000, 29531169256166572959626706182319305835700813824000000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 4^n * Gamma(1 + n + n^2)/Gamma(1 - n + n^2). - G. C. Greubel, May 06 2022
|
|
EXAMPLE
|
a(3) = 14*16*18*20*22*24 = 42577920.
|
|
MATHEMATICA
|
Table[4^n*Gamma[1+n+n^2]/Gamma[1-n+n^2], {n, 30}] (* G. C. Greubel, May 05 2022 *)
|
|
PROG
|
(PARI) { for(n=1, 100, write("b062030.txt", n, " ", 2^(2*n)*(n^2+n)!/(n^2-n)!) ) } \\ Harry J. Smith, Jul 30 2009
(SageMath) [4^n*gamma(1+n+n^2)/gamma(1-n+n^2) for n in (1..30)] # G. C. Greubel, May 05 2022
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|