A373170 Main diagonal of A373169.

1, 3, 9, 22, 45, 81, 43, 24, 288, 118, 138, 585, 184, 918, 288, 232, 294, 351, 559, 2586, 1179, 3586, 117, 72, 3913, 2949, 5949, 1585, 7239, 8811, 3595, 3789, 3537, 5758, 1968, 18, 6454, 4152, 4374, 1687, 549, 7794, 3922, 8313, 828, 2674, 4251, 2646, 5548, 3636, 3879, 799

Offset: 2

Author

Paolo Xausa, May 28 2024

Keywords

• nonn
• base
• easy

Comments

a(n) is the zeroless analog of the (n-1)-th n-gonal number.

Links

• Paolo Xausa, Table of n, a(n) for n = 2..10000

Crossrefs

Cf. A064808, A004719, A373169.

Programs

Mathematica

noz[n_] := FromDigits[DeleteCases[IntegerDigits[n], 0]];
A373170[n_] := Fold[noz[#2*(n-2) + 1 + #] &, 1, Range[n-2]];
Array[A373170, 100, 2]

Formula

a(n) = A373169(n,n-1).