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Cubes of the prime factors (with multiplicity) of n add up to n.
2

%I #52 Sep 14 2019 06:38:52

%S 1096744,2836295,4473671462,23040925705,13579716377989,119429556097859

%N Cubes of the prime factors (with multiplicity) of n add up to n.

%C a(1) = A068916(3).

%C 13579716377989 and 119429556097859 are also terms, but it is not known if they are the next ones. - _Jud McCranie_, Feb 09 2016

%H S. P. Hurd and J. S. McCranie, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL22/Hurd/hurd1.html">Integers that are Sums of Uniform Powers of all their Prime Factors: the sequence A068916</a>, J. of Int. Seq., vol 22 (2019), article 19.3.4.

%e 1096744 = 2^3 * 11^3 * 103 = 2^3+2^3+2^3+11^3+11^3+11^3+103^3.

%o (PARI) isok(n) = {my(f = factor(n)); sum(k=1, #f~, f[k,1]^3*f[k, 2]) == n;} \\ _Michel Marcus_, Feb 09 2016

%Y Cf. A068916, A067688 (a more inclusive sequence), A058041.

%K nonn,more

%O 1,1

%A _Jud McCranie_, Jan 24 2016

%E a(5) from _Jud McCranie_, Feb 13 2016

%E a(6) from _Jud McCranie_, Mar 20 2016