A274389 Main diagonal of rectangular array A274390 of coefficients in the iterations of Euler's tree function (A000169).

1, 2, 30, 948, 50680, 4090980, 463975764, 70311813880, 13718193268896, 3348658563980040, 999698412743754460, 358297471515195652308, 151813934699349280088328, 75064081768759279536110316, 42833194538353991390132088540, 27937122503026656234469859408880, 20653210428143999114034181337343616, 17178393944175652034128269331788145680, 15970217696130529428248774113884778921452, 16497536217367322285994072192399435877530380, 18836957575278690757486149667782477659475272520

Offset

0,2

Links

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

Prog

(PARI) {ITERATE(F, n, k) = my(G=x +x*O(x^k)); for(i=1, n, G=subst(G, x, F)); G}
{A274390(n, k) = my(TREE = serreverse(x*exp(-x +x*O(x^k)))); k!*polcoeff(ITERATE(TREE, n, k), k)}
/* Print A274390 */
for(n=0, 10, for(k=1, 10, print1(A274390(n, k), ", ")); print("..."))
/* Print this sequence, as the main diagonal of A274390 */
for(n=0, 20, print1(A274390(n, n+1), ", "))

Crossrefs

Cf. A274390, A000169, A274392.

Sequence in context: A114938 A082653 A332231 * A186292 A273661 A322624

Adjacent sequences: A274386 A274387 A274388 * A274390 A274391 A274392

Keyword

nonn

Author

Paul D. Hanna, Jun 24 2016

Status

approved