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%I #23 Jan 15 2021 07:43:00
%S 0,2,5,12,37,158,879,5920,46241,409122,4037923,43954724,522956325,
%T 6749977126,93928268327,1401602636328,22324392524329,378011820620330,
%U 6780385526348331,128425485935180332,2561327494111820333
%N a(n) = n - 1 + Sum_{j=0..n} j!.
%F a(n) = A036781(n) - 1.
%F E.g.f.: exp(x-1)*(Ei(1)-Ei(1-x)) + exp(x)*(x-1) + 1/(1-x). - _Robert Israel_, Jan 05 2015
%p N:= 30: # to get a(0) to a(N)
%p C:= ListTools:-PartialSums([seq(j!,j=0..N)]):
%p seq(n-1+C[n+1],n=0..N); # _Robert Israel_, Jan 05 2015
%o (PARI) a(n) = n - 1 + sum(j=0, n, j! ); \\ _Joerg Arndt_, Jan 06 2015
%Y Cf. A036781.
%K nonn
%O 0,2
%A _N. J. A. Sloane_
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