The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A055596 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A055596

Expansion of e.g.f. (2 - x - 2*exp(-x))/(1-x).
(history; published version)

#53 by Joerg Arndt at Mon Jan 01 11:45:42 EST 2024

STATUS

editing

approved

#52 by Paolo P. Lava at Sat Dec 30 13:44:49 EST 2023

FORMULA

a(n) = -n!*(1 + 2*Sum_{k=1..n} (-1)^k/k!), with n>=1. - Paolo P. Lava, Apr 26 2010

STATUS

approved

editing

#51 by Michael De Vlieger at Tue Sep 06 10:29:25 EDT 2022

STATUS

reviewed

approved

#50 by Michel Marcus at Tue Sep 06 02:43:49 EDT 2022

STATUS

proposed

reviewed

#49 by G. C. Greubel at Tue Sep 06 02:08:52 EDT 2022

STATUS

editing

proposed

#48 by G. C. Greubel at Tue Sep 06 02:08:26 EDT 2022

NAME

Expansion of Ee.g.f. (2 - x - 2/*exp(-x))/(1-x).

FORMULA

a(n) = -n!*[(1 + 2*Sum_{k=1..n}{ (-1)^k/k!}], ), with n>=1. - Paolo P. Lava, Apr 26 2010

PROG

(PARI) a(n)=if(n<2, n>0, n*a(n-1)-2*(-1)^n)

(Magma)

A055596:= func< n | Factorial(n)*(1 -2*(&+[(-1)^j/Factorial(j): j in [0..n]]) ) >;

[A055596(n): n in [1..30]]; // G. C. Greubel, Sep 06 2022

(SageMath)

def A055596(n): return factorial(n)*( 2*bool(n==0) + 1 - 2*sum((-1)^j/factorial(j) for j in (0..n)) )

[A055596(n) for n in (1..30)] # G. C. Greubel, Sep 06 2022

STATUS

approved

editing

#47 by Joerg Arndt at Tue Jan 11 11:25:12 EST 2022

STATUS

reviewed

approved

#46 by Wesley Ivan Hurt at Tue Jan 11 11:01:15 EST 2022

STATUS

proposed

reviewed

#45 by Wesley Ivan Hurt at Tue Jan 11 11:01:10 EST 2022

STATUS

editing

proposed

#44 by Wesley Ivan Hurt at Tue Jan 11 11:00:07 EST 2022

NAME

Expansion of E.g.f. (2-x-2/exp(x))/(1-x).

STATUS

proposed

editing