0,2

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Oct 20 2009: (Start)

The asymptotic expansion of the higher order exponential integral E(x,m=1,n=8) ~ exp(-x)/x*(1 - 8/x + 72/x^2 - 720/x^3 + 7920/x^4 - 95040/x^5 + 235520/x^6 - 17297280/x^7 + ...) leads to the sequence given above. See A163931 and A130534 for more information.

(End)

a(n) = (n+7)!/7!; e.g.f.: 1/(1-x)^8.

a:=n->mul(denom( (k+1)/(k+2) ), k=6..n): seq(a(n), n=5..21); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 27 2008

a:=n->mul(numer( (k+1)/(k+2) ), k=7..n): seq(a(n), n=6..22); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 27 2008

restart: G(x):=1/(1-x)^8: f[0]:=G(x): for n from 1 to 16 do f[n]:=diff(f[n-1], x) od: x:=0: seq(f[n], n=0..16); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 01 2009]

Cf. A000142, A001710, A001715, A001720, A001725, A001730, A051339. a(n)= A051379(n, 0)*(-1)^n (first unsigned column of triangle).

Sequence in context: A098411 A165323 A082366 this_sequence A014479 A013992 A129103

Adjacent sequences: A049385 A049386 A049387 this_sequence A049389 A049390 A049391

easy,nonn

Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)