Search: id:A025168 Results 1-1 of 1 results found. %I A025168 %S A025168 1,1,5,37,361,4361,62701,1044205,19748177,417787921,9770678101,250194150581, %T A025168 6959638411705,208919770666777,6729933476435261,231512615111396221,8469125401589550241, %U A025168 328241040596380393505,13434223364220816489637,578931271898150002093381 %N A025168 E.g.f.: exp(x/(1-2*x)). %H A025168 K. A. Penson, P. Blasiak, G. Duchamp, A. Horzela and A. I. Solomon, Hierarchical Dobinski-type relations via substitution and the moment problem [J. Phys. A 37 (2004), 3475-3487] %H A025168 N. J. A. Sloane, Transforms %H A025168 N. J. A. Sloane and Thomas Wieder, The Number of Hierarchical Orderings, Order 21 (2004), 83-89. %H A025168 Thomas Wieder, Expanded definitions of A103446 and A025168 %F A025168 Second LAH transform of A000012. LAH transform of A000262. a(n) = Sum_{k=0..n) 2^(n-k)*n!/k!*binomial(n-1, k-1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 17 2003 %F A025168 Define f_1(x),f_2(x),... such that f_1(x)=e^x, f_{n+1}(x)=diff(x^2*f_n(x), x), for n=2,3,.... Then a(n)=e^{-1/2}*4*{n-1}*f_n(1/2). - Milan R. Janjic (agnus(AT)blic.net), May 30 2008 %p A025168 with(combstruct); SetSeqSeqL := [T, {T=Set(S), S=Sequence(U,card >= 1), U=Sequence(Z,card >=1)},labeled]; %t A025168 Table[ n! 2^n LaguerreL[ n, 1, -1/2 ], {n, 0, 12} ] %Y A025168 Cf. A103446. %Y A025168 Sequence in context: A084212 A004208 A112698 this_sequence A084358 A050351 A129137 %Y A025168 Adjacent sequences: A025165 A025166 A025167 this_sequence A025169 A025170 A025171 %K A025168 nonn %O A025168 0,3 %A A025168 w.meeussen (wouter.meeussen(AT)pandora.be) %E A025168 Corrected and extended by Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 08 2002 Search completed in 0.001 seconds