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A292949
Subsequence of terms of A019278 whose sum of divisors is also a term of A019278.
1
1, 8, 15, 24, 60, 168, 512, 1023, 1536, 4092, 10752, 29127, 47360, 57120, 116508, 331520, 343976, 932064, 1556480, 1980342, 3932040, 4404480, 106151936, 238608384, 251650560, 312792480, 5099962368, 6604416000, 9623577600, 13460388480, 58350015360, 173238912000, 355744082763
OFFSET
1,2
COMMENTS
A019278 is the sequence of integers x such that sigma(sigma(x))/x is an integer.
LINKS
EXAMPLE
8 is a term since both 8 and 15=sigma(8) are terms of A019278.
PROG
(PARI) isok(n) = my(sn=sigma(n), ssn=sigma(sn)); (denominator(ssn/n)==1) && (denominator(sigma(ssn)/sn) == 1);
CROSSREFS
Subsequence of A019278.
Sequence in context: A034114 A069826 A129076 * A072177 A169875 A318111
KEYWORD
nonn
AUTHOR
Michel Marcus, Sep 27 2017
STATUS
approved