A014144 Apply partial sum operator twice to factorials.
0, 1, 3, 7, 17, 51, 205, 1079, 6993, 53227, 462341, 4500255, 48454969, 571411283, 7321388397, 101249656711, 1502852293025, 23827244817339, 401839065437653, 7182224591785967, 135607710526966281, 2696935204638786595, 56349204870460046909, 1234002202313888987223
Offset: 0
Links
- G. C. Greubel, Table of n, a(n) for n = 0..250
- G. V. Milovanovich and A. Petojevich, Generalized Factorial Functions, Numbers and Polynomials, Math. Balkanica, Vol. 16 (2002), Fasc. 1-4.
- Alexsandar Petojevic, The Function vM_m(s; a; z) and Some Well-Known Sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.7.
- Index entries for sequences related to factorial numbers
Programs
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Magma
[(k-1)*(&+[Factorial(j): j in [0..k-1]]) - Factorial(k) + 1: k in [1..25]]; // G. C. Greubel, Sep 03 2018
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Maple
b:= proc(n) option remember; `if`(n<0, [0$2], (q-> (f-> [f[2]+q, q]+f)(b(n-1)))(n!)) end: a:= n-> b(n-1)[1]: seq(a(n), n=0..25); # Alois P. Heinz, Feb 13 2022
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Mathematica
Join[{0}, Accumulate@ Accumulate@ (Range[0, 19]!)] (* Robert G. Wilson v *) Join[{0},Nest[Accumulate[#]&,Range[0,25]!,2]] (* Harvey P. Dale, May 12 2025 *)
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PARI
a(n)=(n-1)*round(n!/exp(1))-n!+1 \\ Charles R Greathouse IV, Feb 24 2011
Formula
a(n) = (n-1) * !n - n! + 1, !n = Sum_{k=0..n-1} k!. - Joe Keane (jgk(AT)jgk.org)
G.f.: x*G(0)/(1-x)^2, where G(k)= 1 + (2*k + 1)*x/( 1 - 2*x*(k+1)/(2*x*(k+1) + 1/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 24 2013
Comments