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A063885 z(sigma(n)) = 2n, where z(n) = A048146. 1
24, 1536, 1631, 47360, 82458 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..5.

PROG

(PARI) u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)); z(n) = sigma(n)-u(n); for(n=1, 10^7, if(z(sigma(n))==2*n, print(n)))

CROSSREFS

Cf. A000203, A034448, A048146, A019284.

Sequence in context: A035174 A288955 A203973 * A019284 A112389 A187634

Adjacent sequences:  A063882 A063883 A063884 * A063886 A063887 A063888

KEYWORD

more,nonn

AUTHOR

Jason Earls, Aug 28 2001

STATUS

approved

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Last modified March 21 22:19 EDT 2019. Contains 321382 sequences. (Running on oeis4.)