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A122627
a(n) = n_t(n) where t() = triangular numbers A000217.
1
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
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
Sequence in context: A082743 A083838 A087082 * A122629 A083477 A069510
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Sep 21 2006
STATUS
approved