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A122628 a(n) = t(n)_t(n) where t() = triangular numbers A000217. 1
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 (list; graph; refs; listen; history; text; internal format)
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: A178850 A018171 A306357 * A343386 A068865 A060179

Adjacent sequences:  A122625 A122626 A122627 * A122629 A122630 A122631

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Sep 21 2006

STATUS

approved

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Last modified November 29 21:32 EST 2021. Contains 349416 sequences. (Running on oeis4.)