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A072463 Shadow transform of sigma(n), A000203, starting with 0, sigma(1), sigma(2), ... 1
0, 1, 1, 2, 2, 1, 2, 2, 2, 1, 1, 1, 3, 2, 3, 2, 1, 1, 3, 1, 2, 2, 1, 1, 4, 1, 1, 1, 2, 1, 3, 3, 3, 1, 1, 1, 3, 1, 2, 2, 2, 1, 4, 1, 2, 2, 1, 1, 5, 1, 1, 1, 1, 1, 3, 1, 3, 2, 1, 1, 6, 1, 3, 2, 1, 1, 1, 1, 2, 1, 1, 1, 8, 1, 2, 1, 1, 1, 2, 1, 3, 1, 1, 1, 6, 1, 1, 1, 1, 1, 5, 2, 1, 3, 1, 1, 5, 1, 3, 1, 1, 1, 2, 1, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..10000

Lorenz Halbeisen and Norbert Hungerbuehler, Number theoretic aspects of a combinatorial function, Notes on Number Theory and Discrete Mathematics 5(4) (1999), 138-150; see Definition 7 for the shadow transform.

N. J. A. Sloane, Transforms.

MAPLE

s:= n-> `if`(n=0, 0, numtheory[sigma](n)):

a:= n-> add(`if`(modp(s(j), n)=0, 1, 0), j=0..n-1):

seq(a(n), n=0..120);  # Alois P. Heinz, Sep 16 2019

CROSSREFS

Cf. A000203.

Sequence in context: A270747 A214517 A230594 * A128853 A136165 A134193

Adjacent sequences:  A072460 A072461 A072462 * A072464 A072465 A072466

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 02 2002

STATUS

approved

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Last modified August 8 14:04 EDT 2020. Contains 336298 sequences. (Running on oeis4.)