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.

A350374 Numbers with exactly 7 semiprime divisors.

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%I A350374 #11 Dec 28 2021 14:51:02
%S A350374 420,630,660,780,840,924,990,1020,1050,1092,1140,1170,1320,1380,1386,
%T A350374 1428,1470,1530,1540,1560,1596,1638,1650,1680,1710,1716,1740,1820,
%U A350374 1848,1860,1890,1932,1950,2040,2070,2142,2184,2220,2244,2280,2380,2394,2436,2460,2508,2550
%N A350374 Numbers with exactly 7 semiprime divisors.
%t A350374 q[n_] := DivisorSum[n, 1 &, PrimeOmega[#] == 2 &] == 7; Select[Range[2500], q] (* _Amiram Eldar_, Dec 28 2021 *)
%o A350374 (PARI) isok(k) = sumdiv(k, d, bigomega(d)==2) == 7; \\ _Michel Marcus_, Dec 28 2021
%Y A350374 Numbers with exactly k semiprime divisors: A346041 (k=1), A345381 (k=2), A345382 (k=3), A350371 (k=4), A350372 (k=5), A350373 (k=6), this sequence (k=7), A350375 (k=8).
%K A350374 nonn
%O A350374 1,1
%A A350374 _Wesley Ivan Hurt_, Dec 27 2021