A122627 a(n) = n_t(n) where t() = triangular numbers A000217.

1, 2, 3, 4, 5, 6, 7, 8, 9, 55, 67, 80, 94, 109, 125, 142, 160, 179, 199, 420, 463, 508, 555, 604, 655, 708, 763, 820, 879, 1395, 1489, 1586, 1686, 1789, 1895, 2004, 2116, 2231, 2349, 3280, 3445, 3614, 3787, 3964, 4145, 4330, 4519, 4712, 4909, 6375, 6631, 6892, 7158

Offset

1,2

Comments

See A122618 for notation.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Maple

a:= n-> (l-> add(l[i]*(n*(n+1)/2)^(i-1), i=1..nops(l)))(convert(n, base, 10)):
seq(a(n), n=1..60);  # Alois P. Heinz, Jul 04 2022

Mathematica

f[n_]:=FromDigits[IntegerDigits@n, n (n + 1) / 2]; Array[f, 64] (* Vincenzo Librandi, Sep 05 2016 *)

Crossrefs

Cf. A000217, A122618.

Sequence in context: A082743 A083838 A087082 * A122629 A083477 A069510

Adjacent sequences: A122624 A122625 A122626 * A122628 A122629 A122630

Keyword

nonn,base

Author

N. J. A. Sloane, Sep 21 2006

Status

approved