

A063991


Unitary amicable numbers.


28



114, 126, 1140, 1260, 18018, 22302, 32130, 40446, 44772, 49308, 56430, 64530, 67158, 73962, 142310, 168730, 180180, 197340, 223020, 241110, 242730, 286500, 296010, 308220, 365700, 429750, 462330, 548550, 591030, 618570, 669900, 671580, 739620, 785148, 815100, 827652, 827700, 932100
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OFFSET

1,1


REFERENCES

C. A. Pickover, The Math Book, Sterling, NY, 2009; see p. 90.


LINKS

Michel Marcus, Table of n, a(n) for n = 1..149
R. M. Najar, The Unitary Amicable Pairs To 10^8
J. M. Pedersen, Known Unitary Amicable Pairs
J. O. M. Pedersen, Tables of Aliquot Cycles [Broken link]
J. O. M. Pedersen, Tables of Aliquot Cycles [Via Internet Archive WaybackMachine]
J. O. M. Pedersen, Tables of Aliquot Cycles [Cached copy, pdf file only]
I. Peterson, Amicable Pairs, Divisors and a New Record
Eric Weisstein's World of Mathematics, Unitary Amicable Pair


PROG

(PARI) f(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d))  n;
isok1(n) = iferr(f(n) == n, E, 0);
isok2(n) = iferr(f(f(n)) == n, E, 0);
isok(n) = isok2(n) && !isok1(n); \\ Michel Marcus, Sep 29 2018


CROSSREFS

Union of A002952 and A002953.
Sequence in context: A057440 A113537 A127664 * A292020 A292019 A065118
Adjacent sequences: A063988 A063989 A063990 * A063992 A063993 A063994


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Sep 18 2001


EXTENSIONS

More terms from Michel Marcus, Sep 29 2018


STATUS

approved



