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 A158882 G.f. A(x) satisfies: [x^n] A(x)^n = [x^n] A(x)^(n-1) for n>1 with A(0)=A'(0)=1. 5
 1, 1, -1, 3, -13, 71, -461, 3447, -29093, 273343, -2829325, 31998903, -392743957, 5201061455, -73943424413, 1123596277863, -18176728317413, 311951144828863, -5661698774848621, 108355864447215063, -2181096921557783605 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS After initial term, equals signed A003319 (indecomposable permutations). LINKS FORMULA a(n) = (2-n) * a(n-1) - Sum_{k=1..n-1} a(k) * a(n-k) if n>1. - Michael Somos, Jul 23 2011 a(n) = (-1)^(n-1)*A003319(n) for n>=1. G.f.: A(x) = 1/[Sum_{n>=0} (-1)^n*n!*x^n]. G.f. satisfies: [x^(n+1)] A(x)^n = (-1)^n*n*A075834(n+1) for n>=0. From Sergei N. Gladkovskii, Jun 24 2012: (Start) Let A(x) be the G.f., then A(x) = 1 - x/U(0), when U(k) =  x - 1 + x*k + (k+2)*x/U(k+1); (continued fraction Euler's 1 kind, 1-step). A(x) = 1/U(0), where U(k) =  1 - x*(2*k+1)/(1 - 2*x*(k+1)/(2*x*(k+1) - 1/U(k+1))); (continued fraction, Euler's 3rd kind, 3-step). (End) G.f.: U(0) where U(k)=  1 + x*(k+1)/(1 + x*(k+1)/U(k+1)); (continued fraction, 2-step). - Sergei N. Gladkovskii, Oct 15 2012 G.f.: 2/(G(0) + 1) where G(k)= 1 - x*(k+1)/(1 - 1/(1 + 1/G(k+1))); (continued fraction, 3-step). - Sergei N. Gladkovskii, Nov 20 2012 G.f.: x*G(0) where G(k)=1/x + 2*k + 1 - (k+1)^2/G(k+1); (recursively defined continued fraction). - Sergei N. Gladkovskii, Dec 08 2012 G.f.: 2/G(0), where G(k)= 1 + 1/(1 - x*(k+1)/(x*(k+1) - 1/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 26 2013 EXAMPLE G.f.: A(x) = 1 + x - x^2 + 3*x^3 - 13*x^4 + 71*x^5 - 461*x^6 +-... 1/A(x) = 1 - x + 2*x^2 - 6*x^3 + 24*x^4 +...+ (-1)^n*n!*x^n +... ... Coefficients of powers of g.f. A(x) begin: A^1: 1,1,(-1),3,-13,71,-461,3447,-29093,273343,-2829325,...; A^2: 1,2,(-1),(4),-19,110,-745,5752,-49775,476994,-5016069,...; A^3: 1,3, 0, (4),(-21),129,-910,7242,-64155,626319,-6685548,...; A^4: 1,4, 2, 4, (-21),(136),-996,8152,-73811,733244,-7938186,...; A^5: 1,5, 5, 5, -20, (136),(-1030),8650,-79925,807055,-8854741,...; A^6: 1,6, 9, 8, -18, 132, (-1030),(8856),-83385,855010,-9500385,...; A^7: 1,7,14,14, -14, 126, -1008, (8856),(-84861),882805,-9927890,...; A^8: 1,8,20,24, -6, 120, -972, 8712, (-84861),(894928),-10180120,...; A^9: 1,9,27,39,9,117,-927,8469,-83772,(894928),(-10291986),...; A^10:1,10,35,60,35,122,-875,8160,-81890,885620,(-10291986),...; ... where coefficients [x^n] A(x)^n and [x^n] A(x)^(n-1) are enclosed in parenthesis and equal (-1)^n*n*A075834(n+1): [ -1,4,-21,136,-1030,8856,-84861,894928,-10291986,128165720,...]; compare to A075834: [1,1,1,2,7,34,206,1476,12123,111866,1143554,12816572,...] and also to the logarithmic derivative of A075834: [1,1,4,21,136,1030,8856,84861,894928,10291986,128165720,...]. MATHEMATICA b[0] = 0; b[n_] := b[n] = n!-Sum[k!*b[n-k], {k, 1, n-1}]; a[0] = 1; a[n_] := (-1)^(n+1)*b[n]; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Mar 07 2014, from 2nd formula *) PROG (PARI) a(n)=polcoeff(1/sum(k=0, n, (-1)^k*k!*x^k +x*O(x^n)), n) (PARI) {a(n)=local(A=[1, 1]); for(i=2, n, A=concat(A, 0); A[ #A]=(Vec(Ser(A)^(#A-2))-Vec(Ser(A)^(#A-1)))[ #A]); A[n+1]} (Maxima) G(n, k):=(if n=k then 1 else if k=1 then (-sum(binomial(n-1, k-1)*G(n, k), k, 2, n)) else sum(G(i+1, 1)*G(n-i-1, k-1), i, 0, n-k)); makelist(G(n, 1), n, 1, 10); /* Vladimir Kruchinin, Mar 07 2014 */ CROSSREFS Cf. A003319, A075834, A159311, variant: A158883. Sequence in context: A167894 A003319 * A233824 A192239 A192936 A000261 Adjacent sequences:  A158879 A158880 A158881 * A158883 A158884 A158885 KEYWORD sign AUTHOR Paul D. Hanna, Apr 30 2009 STATUS approved

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