A134616 Numbers such that the sum of squares of their prime factors (taken with multiplicity) is a prime.
6, 10, 12, 14, 26, 34, 40, 45, 54, 56, 63, 74, 75, 80, 90, 94, 96, 99, 104, 105, 126, 134, 146, 147, 152, 153, 171, 176, 184, 194, 206, 207, 231, 232, 234, 250, 261, 273, 274, 296, 300, 306, 326, 328, 334, 342, 344, 345, 350, 357, 363, 369, 376, 384, 386, 387
Offset: 1
Keywords
Examples
a(2)=10, since 10=2*5 and 2^2+5^2=29 which is prime.
Links
- Hieronymus Fischer, Table of n, a(n) for n = 1..10000
Crossrefs
Programs
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Mathematica
f[{a_,b_}]:=Table[a,b];Select[Range[2,387],PrimeQ[ Total[Flatten[(f/@FactorInteger[#])^2]] ]&] (* James C. McMahon, Apr 09 2025 *)
Extensions
Minor edits by the author, May 06 2013