A092797 Number of connected relations.

1, 667, 108817, 10796275, 858251401, 61283936827, 4147211888737, 273109341611395, 17736960725057401, 1143745441025278987, 73483870162431314257, 4712360023676936085715, 301901195708380781658601, 19331914197940256185117147, 1237580377249840094294765377

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..550

G. Kilibarda and V. Jovovic, Enumeration of some classes of T_0-hypergraphs, arXiv:1411.4187 [math.CO], 2014.

Formula

a(n) = 64^n - 6*33^n - 15*19^n + 30*18^n - 10*15^n + 120*12^n - 120*11^n + 30*10^n - 270*9^n + 360*8^n - 120*7^n.

G.f.: x*(54888451200*x^9 +55706052240*x^8 -14450714964*x^7 -624924*x^6 +247511131*x^5 -22659769*x^4 +564934*x^3 +10694*x^2 -461*x -1) / ((7*x -1)*(8*x -1)*(9*x -1)*(10*x -1)*(11*x -1)*(12*x -1)*(15*x -1)*(18*x -1)*(19*x -1)*(33*x -1)*(64*x -1)). - Colin Barker, Jul 13 2013

Mathematica

Table[64^n - 6*33^n - 15*19^n + 30*18^n - 10*15^n + 120*12^n - 120*11^n  + 30*10^n - 270*9^n + 360*8^n - 120*7^n, {n, 0, 50}] (* G. C. Greubel, Oct 08 2017 *)

Prog

(PARI) for(n=0, 50, print1(64^n - 6*33^n - 15*19^n + 30*18^n - 10*15^n + 120*12^n - 120*11^n  + 30*10^n - 270*9^n + 360*8^n - 120*7^n, ", ")) \\ G. C. Greubel, Oct 08 2017
(Magma) [64^n - 6*33^n - 15*19^n + 30*18^n - 10*15^n + 120*12^n - 120*11^n  + 30*10^n - 270*9^n + 360*8^n - 120*7^n: n in [0..50]]; // G. C. Greubel, Oct 08 2017

Crossrefs

Cf. A005333, A001047, A002501, A002502, A093732, A093733.

Sequence in context: A210477 A138563 A327908 * A105212 A067875 A224558

Adjacent sequences: A092794 A092795 A092796 * A092798 A092799 A092800

Keyword

nonn,easy

Author

Goran Kilibarda, Vladeta Jovovic, Apr 15 2004

Extensions

More terms from Colin Barker, Jul 13 2013

Status

approved