login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A082403 E.g.f.: 1-1/B(x) where B(x) is e.g.f. for A003024. 1
0, 1, 1, 13, 373, 24061, 3430021, 1085594413, 765444156373, 1199327541421981, 4150826776751106181, 31511604323119334675053, 521181162682913685911315413, 18663030289006900328937074926621 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

REFERENCES

R. W. Robinson, Counting labeled acyclic digraphs, p. 264 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..50

MATHEMATICA

m = 20; b[0] = b[1] = 1;

b[n_] := b[n] = Sum[-(-1)^k Binomial[n, k] 2^(k (n-k)) b[n-k], {k, 1, n}];

B[x_] = Sum[b[n] x^n/n!, {n, 0, m}];

CoefficientList[1 - 1/B[x] + O[x]^(m+1), x] Range[0, m]! (* Jean-Fran├žois Alcover, Jan 24 2020 *)

PROG

(PARI) \\ here G(n) gives A003024 as e.g.f.

G(n)={my(v=vector(n+1)); v[1]=1; for(n=1, n, v[n+1]=sum(k=1, n, -(-1)^k*2^(k*(n-k))*v[n-k+1]/k!))/n!; Ser(v)}

{ concat([0], Vec(serlaplace(1-1/G(15)))) } \\ Andrew Howroyd, Sep 10 2018

CROSSREFS

Cf. A003024.

Sequence in context: A009040 A009085 A012013 * A171656 A320458 A320635

Adjacent sequences:  A082400 A082401 A082402 * A082404 A082405 A082406

KEYWORD

nonn

AUTHOR

Vladeta Jovovic, Apr 15 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 29 19:22 EDT 2020. Contains 338068 sequences. (Running on oeis4.)