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A260508 Numbers n such that A000203(n) == n*A001221(n). 1

%I #7 Jul 28 2015 05:36:13

%S 6,28,120,496,672,8128,30240,33550336,8589869056,137438691328

%N Numbers n such that A000203(n) == n*A001221(n).

%C Subsequence of A007691.

%C a(n) is in A000396 iff A001221(a(n)) == 2, i.e., if a(n) is in A007774.

%C a(11) > 2.5*10^12. - _Giovanni Resta_, Jul 28 2015

%o (PARI) is(n) = sigma(n)==n*omega(n)

%Y Cf. A000396, A007691.

%K nonn,more

%O 1,1

%A _Felix Fröhlich_, Jul 27 2015

%E a(9)-a(10) from _Giovanni Resta_, Jul 28 2015

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)