A102289 Total number of odd lists in all sets of lists, cf. A000262.
0, 1, 2, 15, 76, 665, 5286, 56287, 597080, 7601841, 99702730, 1484554511, 23049638052, 393702612745, 7036703742446, 135702811542495, 2737989749177776, 58848546456947297, 1321063959370833810, 31310238786268648591, 773291778432688011260, 20031956775840631151481
Offset: 0
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..444
Programs
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Maple
G:=(x/(1-x^2))*exp(x/(1-x)): Gser:=series(G,x=0,25): seq(n!*coeff(Gser,x^n),n=1..22); # Emeric Deutsch # second Maple program: b:= proc(n) option remember; `if`(n=0, [1, 0], add( (p-> p+`if`(j::odd, [0, p[1]], 0))(b(n-j)* binomial(n-1, j-1)*j!), j=1..n)) end: a:= n-> b(n, 0)[2]: seq(a(n), n=0..25); # Alois P. Heinz, May 10 2016
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Mathematica
Rest[CoefficientList[Series[x/(1-x^2)*E^(x/(1-x)), {x, 0, 20}], x]* Range[0, 20]!] (* Vaclav Kotesovec, Sep 29 2013 *) nxt[{n_,a_,b_,c_}]:={n+1,b,c,(n+1)*c+(n+1)^2*b-(n-1)^2 (n+1)*a}; NestList[ nxt,{2,0,1,2},30][[All,2]] (* Harvey P. Dale, Jan 13 2019 *)
Formula
E.g.f.: x/(1-x^2)*exp(x/(1-x)).
a(n) = n*a(n-1) + n^2*a(n-2) - (n-2)^2*n*a(n-3). - Vaclav Kotesovec, Sep 29 2013
a(n) ~ sqrt(2)/4 * n^(n+1/4)*exp(2*sqrt(n)-n-1/2) * (1 + 7/(48*sqrt(n))). - Vaclav Kotesovec, Sep 29 2013
Extensions
More terms from Emeric Deutsch, Jun 24 2005
a(0)=0 pepended by Alois P. Heinz, May 10 2016