A212483 Smallest number k such that the sum of the distinct prime divisors of k equals n times a prime.
2, 21, 14, 15, 21, 35, 33, 39, 65, 51, 57, 95, 69, 115, 86, 87, 93, 155, 217, 111, 122, 123, 129, 215, 141, 235, 158, 159, 265, 371, 177, 183, 194, 427, 201, 335, 213, 219, 365, 511, 237, 395, 249, 415, 446, 267, 278, 623, 1246, 291, 302, 303, 309, 515, 321
Offset: 1
Keywords
Examples
a(5) = 21 because 21 = 3*7 and 3 + 7 = 10 = 5*2 where 2 is prime.
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..5000
Programs
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Maple
with (numtheory): sopf:= proc(n) option remember; add(i, i=factorset(n)) end: a:= proc(n) local k, p; for k from 2 while irem(sopf(k), n, 'p')>0 or not isprime(p) do od; k end: seq (a(n), n=1..100); # Alois P. Heinz, Jun 03 2012 -
Mathematica
snk[n_]:=Module[{k=1},While[!PrimeQ[(Total[Transpose[ FactorInteger[k]] [[1]]])/n],k++];k]; Array[snk,60] (* Harvey P. Dale, Jun 24 2013 *)
Comments