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A063973 a(n) is the largest m such that usigma(m) = n (or 0 if no such m). 2
1, 0, 2, 3, 4, 5, 0, 7, 8, 9, 0, 11, 0, 13, 0, 0, 16, 17, 0, 19, 0, 0, 0, 23, 0, 25, 0, 27, 0, 29, 0, 31, 32, 0, 0, 24, 0, 37, 0, 28, 0, 41, 0, 43, 0, 0, 0, 47, 0, 49, 0, 0, 0, 53, 0, 39, 0, 0, 0, 59, 0, 61, 0, 0, 64, 0, 0, 67, 0, 52, 0, 71, 0, 73, 0, 0, 0, 50, 0, 79, 0, 81, 0, 83, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

usigma(m) is the sum of unitary divisors of m, A034448.

LINKS

Daniel Suteu, Table of n, a(n) for n = 1..10000

EXAMPLE

a(12)=11 because the unitary divisors of 11 are 1,11; they sum to 12.

CROSSREFS

Cf. A034444, A034448, A051444, A057637, A063972.

Sequence in context: A224892 A265517 A063972 * A126441 A004181 A080744

Adjacent sequences:  A063970 A063971 A063972 * A063974 A063975 A063976

KEYWORD

nonn

AUTHOR

Labos Elemer, Sep 05 2001

EXTENSIONS

Corrected by Don Reble, May 14 2006

STATUS

approved

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Last modified April 21 14:20 EDT 2021. Contains 343154 sequences. (Running on oeis4.)