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 A059099 Expansion of exp(exp(x)-1)/(2-exp(x)). 4
 1, 2, 7, 33, 198, 1453, 12669, 128320, 1482721, 19260421, 277913552, 4410640919, 76360030701, 1432144732762, 28926138244883, 625974400305541, 14449445989893990, 354384475357492593, 9202837263156670345 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Row sums of A227343. - Peter Bala, Jul 11 2013 The sequence gives the number of barred preferential arrangements of an n-set having one bar, where one fixed section is a free section and elements which are to go into the other section are partitioned into unordered nonempty subsets. - Sithembele Nkonkobe, Jul 02 2015 LINKS S. Nkonkobe and V. Murali, A study of a family of generating functions of Nelsen-Schmidt type and some identities on restricted barred preferential arrangements, arXiv:1503.06172 [math.CO], 2015. FORMULA a(n) = Sum_{m=0..n} Sum_{i=0..n} stirling2(n, i)*Product_{j=1..m} (i-j+1). Stirling transform of A000522. - Vladeta Jovovic, May 10 2004 a(n) ~ n!*exp(1)/(2*(log(2))^(n+1)). - Vaclav Kotesovec, Jul 02 2015 EXAMPLE exp(exp(x)-1)/(2-exp(x)) = 1 + 2*x + 7/2*x^2 + 11/2*x^3 + 33/4*x^4 + 1453/120*x^5 + 4223/240*x^6 + 1604/63*x^7 + ... MAPLE s := series(exp(exp(x)-1)/(2-exp(x)), x, 60): for i from 0 to 50 do printf(`%d, `, i!*coeff(s, x, i)) od: MATHEMATICA CoefficientList[Series[E^(E^x-1)/(2-E^x), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jul 02 2015 *) CROSSREFS Row sums of A059098. Cf. A001861, A000110, A005493, A049020, A227343. Sequence in context: A006595 A179525 A217033 * A020103 A014623 A144005 Adjacent sequences:  A059096 A059097 A059098 * A059100 A059101 A059102 KEYWORD easy,nonn AUTHOR Vladeta Jovovic, Jan 02 2001 EXTENSIONS More terms from James A. Sellers, Jan 03 2001 STATUS approved

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Last modified December 13 08:08 EST 2018. Contains 318082 sequences. (Running on oeis4.)