[go: up one dir, main page]

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”).

a(n) = 24*5^n - 60*4^n + 50*3^n - 15*2^n + 1.
3

%I #9 Oct 21 2022 09:48:11

%S 0,1,31,391,3451,25231,164731,999391,5767051,32122831,174397531,

%T 929043391,4879252651,25349936431,130617150331,668714319391,

%U 3406562690251,17286209766031,87448932863131,441329102667391,2223021985199851,11180731992411631,56166496811775931,281884877304327391

%N a(n) = 24*5^n - 60*4^n + 50*3^n - 15*2^n + 1.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (15,-85,225,-274,120).

%F a(n) = Sum_{i=1..n} i!*i^4*Stirling2(n, i)*(-1)^(n-i).

%t Table[24*5^n - 60*4^n + 50*3^n - 15*2^n + 1, {n, 0, 25}]

%o (PARI) a(n) = sum(i=1, n, i!*i^4*stirling(n, i, 2)*(-1)^(n-i)); \\ _Michel Marcus_, Oct 21 2022

%Y Cf. A091344, A091347.

%K nonn,easy

%O 0,3

%A Mario Catalani (mario.catalani(AT)unito.it), Jan 03 2004

%E More terms from _Michel Marcus_, Oct 21 2022