A393930 a(0) = 0, a(1) = 1; a(n) = n! * [x^n] (1/n)^2 * exp(n*x) * Sum_{k=1..n-1} a(k)*x^k/k!.

0, 1, 1, 4, 26, 241, 2947, 45248, 843732, 18661671, 481146211, 14268787628, 481575324194, 18335512686481, 781646971249603, 37063676993936908, 1943284729431092340, 112059055358657319023, 7072342296849963327347, 486361147949618853157892

Offset

0,4

Links

Table of n, a(n) for n=0..19.

Formula

a(n) = Sum_{k=1..n-1} n^(k-2) * binomial(n,k) * a(n-k) for n > 1.

Crossrefs

Cf. A089918, A293860.

Sequence in context: A302606 A052577 A203935 * A210912 A210913 A210914

Adjacent sequences: A393926 A393927 A393928 * A393931 A393932 A393933

Keyword

nonn

Author

Seiichi Manyama, Mar 03 2026

Status

approved