A298881 - OEIS

%I #20 Sep 08 2022 08:46:20

%S 0,6,12,36,144,720,4320,30240,241920,2177280,21772800,239500800,

%T 2874009600,37362124800,523069747200,7846046208000,125536739328000,

%U 2134124568576000,38414242234368000,729870602452992000,14597412049059840000,306545653030256640000

%N a(0) = 0; for n>0, a(n) = 6*n!.

%H Vincenzo Librandi, <a href="/A298881/b298881.txt">Table of n, a(n) for n = 0..300</a>

%F E.g.f.: 6*x/(1-x).

%F a(n) = n*a(n-1) = 6*A000142(n) for n>0.

%t Join[{0}, 6 Range[25]!]

%o (Magma) [n eq 0 select 0 else 6*Factorial(n): n in [0..25]];

%o (GAP) Concatenation([0], List([1..25], n -> 6*Factorial(n))); # _Bruno Berselli_, Feb 13 2018

%o (PARI) a(n) = if (n, 6*n!, 0); \\ _Michel Marcus_, Feb 15 2018

%Y Cf. A274266.

%Y Cf. sequences of the type k*n!: A000142 (k=1), A052849 (k=2), A052560 (k=3), A052578 (k=4), A052648 (k=5), this sequence (k=6), A062098 (k=7), A159038 (k=8), A174183 (k=10).

%K nonn,easy

%O 0,2

%A _Vincenzo Librandi_, Feb 13 2018

%E Edited by _Bruno Berselli_, Feb 13 2018