Search: id:A052169 Results 1-1 of 1 results found. %I A052169 %S A052169 1,2,5,19,91,531,3641,28673,254871,2523223,27526069,328018989, %T A052169 4239014627,59043418019,881715042417,14052333488521,238063061452591, %U A052169 4271909380510383,80941440893880941,1614781745832924773 %N A052169 Equivalent of the Kurepa hypothesis for left factorial. %C A052169 a(n)=A002467(n)/(n-1) (A002467(n)=number of non-derangements of {1,2, ...,n}). [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 15 2009] %H A052169 Alexsandar Petojevic, The Function vM_m(s; a; z) and Some Well-Known Sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.7 %F A052169 a(2) = 1, a(3) = 2, a(n) = (n-2)*a(n-1) + (n-3)*a(n-2) %p A052169 a[2] := 1: a[3] := 2: for n from 4 to 21 do a[n] := (n-2)*a[n-1]+(n-3)*a[n-2] end do: seq(a[n], n = 2 .. 21); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 15 2009] %t A052169 Numerator[k=1; NestList[1+1/(k++ #1)&,1,12]] - Wouter Meeussen (wouter.meeussen(AT)pandora.be), Mar 24 2007 %o A052169 (Other) sage: from sage.combinat.sloane_functions import ExtremesOfPermanentsSequence2 sage: e = ExtremesOfPermanentsSequence2() sage: it = e.gen(1,2,1) sage: [it.next() for i in range(20)] #(5 rows)# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 15 2009] %Y A052169 Pairwise sums of A002467. %Y A052169 Sequence in context: A052324 A020115 A103816 this_sequence A020019 A020109 A020015 %Y A052169 Adjacent sequences: A052166 A052167 A052168 this_sequence A052170 A052171 A052172 %K A052169 nonn,easy %O A052169 2,2 %A A052169 Aleksandar Petojevic (apetoje(AT)ptt.yu), Jan 26 2000 %E A052169 More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jan 31 2000 Search completed in 0.001 seconds