1,2

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 262.

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 262.

E.g.f.: exp(-3x)/(1-x). - Michael Somos Mar 06 2004

a(0) = 1 and for n>0, a(n) is the permanent of the n X n matrix with -2's on the diagonal and 1's elsewhere. a(n) = Sum(k=0..n, A008290(n, k)*(-2)^k ). a(n) = Sum(k=0..n, A008279(n, k)*(-3)^(n-k) ). - DELEHAM Philippe (kolotoko(AT)wanadoo.fr), Dec 15 2003

a:=n->n!*sum(((-3)^(k)/k!), k=0..n): seq(a(n), n=0..21); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 22 2007

Table[ Gamma[ n, -3 ]*E^3, {n, 1, 24} ]

(PARI) a(n)=if(n<0, 0, n!*polcoeff(exp(-3*x+x*O(x^n))/(1-x), n)) - Michael Somos Mar 06 2004

(PARI) a(n)=local(A, p); if(n<1, n==0, A=matrix(n, n, i, j, 1-3*(i==j)); sum(i=1, n!, if(p=numtoperm(n, i), prod(j=1, n, A[j, p[j]])))) - Michael Somos Mar 06 2004

See also A000023 A000166 A000142 A000522 A010842 A053486 A053487 A080954 A080955

Cf. A008279 A008279 A089258.

Sequence in context: A148284 A148285 A115523 this_sequence A084075 A000560 A032124

Adjacent sequences: A010840 A010841 A010842 this_sequence A010844 A010845 A010846

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Simon Plouffe (simon.plouffe(AT)gmail.com)