A122628 a(n) = t(n)_t(n) where t() = triangular numbers A000217.

1, 3, 6, 10, 20, 43, 64, 114, 185, 280, 402, 554, 820, 11030, 14640, 18910, 24177, 30439, 37810, 88410, 107416, 129286, 154290, 270000, 317530, 371359, 431306, 659350, 758210, 867695, 988534, 1394984, 1576972, 1775485, 2383290, 2665338, 3459466, 3846532

Offset

1,2

Comments

See A122618 for notation.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Maple

a:= n-> (b-> (l-> add(l[i]*b^(i-1),
    i=1..nops(l)))(convert(b, base, 10)))(n*(n+1)/2):
seq(a(n), n=1..35);  # Alois P. Heinz, Apr 10 2021

Crossrefs

Sequence in context: A018171 A306357 A365694 * A343386 A068865 A060179

Adjacent sequences: A122625 A122626 A122627 * A122629 A122630 A122631

Keyword

nonn,base

Author

N. J. A. Sloane, Sep 21 2006

Status

approved