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A225792 Numbers n such that the sum of first n nontrivial prime powers (A025475 excluding 1) is divisible by n. 2

%I #10 May 16 2013 11:38:23

%S 1,2,3,9,13,54,384,596,7289,18136,226871,1577601,5240465,13389981,

%T 130707763,157598052,617834651,998713177,4596574856

%N Numbers n such that the sum of first n nontrivial prime powers (A025475 excluding 1) is divisible by n.

%C a(16) > 146306912. There are 146306912 nontrivial prime powers <= 2^63. - _Donovan Johnson_, May 16 2013

%C a(20) > 41.2*10^9. - _Giovanni Resta_, May 16 2013

%e The sum of first 9 nontrivial prime powers is 4 + 8 + 9 + 16 + 25 + 27 + 32 + 49 + 64 = 234. Because 234 is divisible by 9, the latter is in the sequence.

%Y Cf. A025475, A225791.

%K nonn,more

%O 1,2

%A _Alex Ratushnyak_, May 16 2013

%E a(12)-a(15) from _Donovan Johnson_, May 16 2013

%E a(16)-a(19) from _Giovanni Resta_, May 16 2013

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)