A274388 Main diagonal of rectangular array A274391 of coefficients in functions that satisfy W_n(x) = W_{n-1}(x)^W_n(x), with W_0(x) = exp(x).

1, 1, 5, 82, 2729, 151376, 12567187, 1457297878, 224869459201, 44538286061152, 11011493721321251, 3323602336722922574, 1202633627172086804257, 513869583003728865617848, 255985770924976071728925555, 147050140379016992236158750526, 96489590122440823908683879560193, 71722476615114676804476795900453248, 59952692198711311645811325484552353091, 55990325778560798795385664699772933184190, 58081532846176563089250398770056580653829601

Offset: 0

Author

Paul D. Hanna, Jun 24 2016

Keywords

• nonn

Links

• Paul D. Hanna, Table of n, a(n) for n = 0..100

Crossrefs

Cf. A274391, A274387, A274389.

Programs

PARI

{ITERATE(F,n,k) = my(G=x +x*O(x^k)); for(i=1,n,G=subst(G,x,F));G}
{A274391(n,k) = my(TREE = serreverse(x*exp(-x +x*O(x^k)))); k!*polcoeff(exp(ITERATE(TREE,n,k)),k)}
/* Print table A274391 */
for(n=0,10,for(k=0,10,print1(A274391(n,k),", "));print("..."))
/* Print this sequence as the main diagonal in A274391 */
for(n=0,20,print1(A274391(n,n),", "))