A397777 Antidiagonal sums of the array A397775.

1, 2, 5, 15, 53, 228, 1209, 7747, 58225, 500544, 4832313, 51687383, 606215565, 7731822692, 106508476905, 1575578081523, 24906716310217, 418953742412128, 7470858290454729, 140766571939157751, 2794339758909240773, 58286364420483563796, 1274476812220456366841, 29150033296842803410371

Offset

0,2

Links

Table of n, a(n) for n=0..23.

Formula

a(n) = Sum_{k=0..n} A397775(n-k, k).

Mathematica

A397775[0, k_]:=1; A397775[n_, k_]:=A397775[n, k]=n*A397775[n-1, k]+k; a[n_]:=Sum[A397775[n-k, k], {k, 0, n}]; Array[a, 24, 0]

Crossrefs

Cf. A397775.

Sequence in context: A006966 A336020 A277175 * A056841 A390195 A378939

Adjacent sequences: A397771 A397775 A397776 * A397778 A397787 A397788

Keyword

nonn,new

Author

Stefano Spezia, Jul 09 2026

Status

approved