A111491 a(0) = 1; for n>0, a(n) = (2^n-1)*a(n-1)-(-1)^n.

1, 2, 5, 36, 539, 16710, 1052729, 133696584, 34092628919, 17421333377610, 17822024045295029, 36481683220718924364, 149392492788843995270579, 1223673908433421165261312590, 20047449641864738950476084161969, 656894782414981901190249849735238224

Offset: 0

Author

N. J. A. Sloane, Nov 28 2005, typo corrected Nov 21 2008

Keywords

• nonn

References

• W. T. Trotter, Combinatorics and Partially Ordered Sets, Johns Hopkins, 1992; see p. 195.

Crossrefs

Cf. A111968.

Programs

Maple

s:=proc(n) option remember; if n=0 then 1 else (2^n-1)*s(n-1)-(-1)^n; fi; end;

Mathematica

RecurrenceTable[{a[0]==1,a[n]==(2^n-1)a[n-1]-(-1)^n},a,{n,20}] (* Harvey P. Dale, Dec 11 2012 *)