cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A380098 Numbers whose sum of cubes of distinct prime factors is prime.

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%I A380098 #10 Jan 14 2025 10:26:32
%S A380098 165,210,390,399,420,462,495,561,570,595,615,630,651,780,798,825,840,
%T A380098 924,957,1050,1085,1140,1170,1173,1197,1218,1235,1245,1260,1302,1386,
%U A380098 1435,1470,1482,1485,1495,1554,1560,1596,1615,1680,1683,1705,1710,1767,1771,1815,1845,1848,1885,1890,1938,1950,1953
%N A380098 Numbers whose sum of cubes of distinct prime factors is prime.
%e A380098 165=3*5*11 and 3^3 + 5^3 + 11^3 = 1483, which is prime. Therefore, 165 is included.
%p A380098 a:=proc(n) local DPF: DPF:=factorset(n): if isprime(sum(DPF[j]^3, j=1..nops(DPF)))=true then n else fi end: seq(a(n), n=1..2000);
%t A380098 Select[Range[2000], PrimeQ[Total[Transpose[FactorInteger[#]][[1]]^3]]&]
%o A380098 (Python)
%o A380098 from sympy import isprime, factorint
%o A380098 def ok(n): return isprime(sum(p**3 for p in factorint(n)))
%o A380098 print([k for k in range(2000) if ok(k)]) # _Michael S. Branicky_, Jan 12 2025
%Y A380098 Cf. A005064, A114522, A114989.
%K A380098 nonn
%O A380098 1,1
%A A380098 _Rafik Khalfi_, Jan 12 2025