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A019289 Let sigma_m (n) be result of applying sum-of-divisors function m times to n; call n (m,k)-perfect if sigma_m (n) = k*n; sequence gives the (2,12)-perfect numbers. 0
2200380, 8801520, 14913024, 35206080, 140896000, 459818240, 775898880, 2253189120, 16785793024, 22648550400, 36051025920, 51001180160, 144204103680 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See also the Cohen-te Riele links under A019276.

No others < 5x10^11. - Jud McCranie, Feb 08 2012

LINKS

Table of n, a(n) for n=1..13.

Graeme L. Cohen and Herman J. J. te Riele, Iterating the sum-of-divisors function, Experimental Mathematics, 5 (1996), pp. 93-100.

CROSSREFS

Sequence in context: A224588 A234332 A251342 * A254803 A254810 A253819

Adjacent sequences:  A019286 A019287 A019288 * A019290 A019291 A019292

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Jud McCranie, Nov 13 2001, a(9) Feb 01 2012, a(10)-a(13) on Feb 08 2012

STATUS

approved

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Last modified July 19 12:26 EDT 2019. Contains 325159 sequences. (Running on oeis4.)