This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A062740 Number of connected labeled graphs with loops. 5
 1, 2, 4, 32, 608, 23296, 1709056, 238880768, 64396439552, 33943701028864, 35324404321091584, 72994114660256448512, 300460426062916084563968, 2468021884106048216693211136, 40495494119922790159005962469376 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..80 FORMULA E.g.f.: 1+log( Sum_{n >= 0} 2^binomial(n+1, 2)*x^n/n! ). E.g.f.: A(2*x) where A(x) is the e.g.f. for A001187. - Geoffrey Critzer, Feb 01 2014 MAPLE logtr:= proc(p) local b; b:= proc(n) option remember; if n=0 then 1 else p(n)- add(k *binomial(n, k) *p(n-k) *b(k), k=1..n-1)/n fi end end: a:= logtr(n-> 2^binomial(n+1, 2)): seq(a(n), n=0..20);  # Alois P. Heinz, Feb 01 2014 MATHEMATICA nn=14; g=Sum[2^Binomial[n, 2](2x)^n/n!, {n, 0, nn}]; Range[0, nn]!CoefficientList[Series[Log[g]+1, {x, 0, nn}], x] (* Geoffrey Critzer, Feb 01 2014 *) CROSSREFS Cf. A006125, A226773. Sequence in context: A304862 A118992 A012509 * A122214 A122216 A100117 Adjacent sequences:  A062737 A062738 A062739 * A062741 A062742 A062743 KEYWORD easy,nonn AUTHOR Vladeta Jovovic, Jul 12 2001 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.

Last modified October 16 16:18 EDT 2019. Contains 328101 sequences. (Running on oeis4.)