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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A049414 Number of quasi-initially connected digraphs with n labeled nodes. 3
 1, 3, 54, 3804, 1022320, 1065957628, 4389587378792, 72020744942708040, 4721708591209396542528, 1237892622263984613044109216, 1298060581376190776821670648395840 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS We say that a node v of a digraph is a quasi-source iff for every other node u there exists directed path from u to v or from v to u. A digraph with at least one quasi-source is called quasi-initially connected. LINKS V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected digraphs, Discrete Math., 224 (2000), 151-163. FORMULA The recurrence formulas are too long to be presented here. CROSSREFS Cf. A003027, A003028, A003029, A003030. Row sums of A057272. Sequence in context: A091796 A171213 A006025 * A003027 A054545 A158103 Adjacent sequences:  A049411 A049412 A049413 * A049415 A049416 A049417 KEYWORD nonn AUTHOR Vladeta Jovovic, Goran Kilibarda 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 August 6 11:55 EDT 2020. Contains 336246 sequences. (Running on oeis4.)