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A111491
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a(0) = 1; for n>0, a(n) = (2^n-1)*a(n-1)-(-1)^n.
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1
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1, 2, 5, 36, 539, 16710, 1052729, 133696584, 34092628919, 17421333377610, 17822024045295029, 36481683220718924364, 149392492788843995270579, 1223673908433421165261312590, 20047449641864738950476084161969, 656894782414981901190249849735238224
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| W. T. Trotter, Combinatorics and Partially Ordered Sets, Johns Hopkins, 1992; see p. 195.
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MAPLE
| s:=proc(n) option remember; if n=0 then 1 else (2^n-1)*s(n-1)-(-1)^n; fi; end;
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CROSSREFS
| Cf. A111968.
Sequence in context: A059586 A160968 A086832 * A163499 A086218 A202637
Adjacent sequences: A111488 A111489 A111490 * A111492 A111493 A111494
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Nov 28 2005, typo corrected Nov 21 2008
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