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.

A258374 Least primitive weird number with n prime divisors, not counting multiplicity.

This page as a plain text file.
%I A258374 #27 Feb 18 2018 11:36:56
%S A258374 70,4030,4199030,1550860550
%N A258374 Least primitive weird number with n prime divisors, not counting multiplicity.
%C A258374 A proper subset of A002975.
%C A258374 So far all terms are == 2 (mod 4).
%C A258374 From _M. F. Hasler_, Jul 18 2016: (Start)
%C A258374 a(3) = 2 * 5 * 7 = A002975(1) = A258882(1),
%C A258374 a(4) = 2 * 5 * 13 * 31 = A258401(1) = A258883(1),
%C A258374 a(5) = 2 * 5 * 11 * 59 * 647 = A258884(1),
%C A258374 a(6) = 2 * 5^2 * 29 * 37 * 137 * 211 = A258885(1) = A273815(1). (End)
%C A258374 a(7) <= 4 * 13 * 17 * 449 * 24809 * 228259243 * 11449243661 ≈ 2.6e28, a(8) <= 4 * 13 * 17 * 449 * 24809 * 223842061 * 1123622795959 * 16039588627050434791 ≈ 3.97 e49. - _M. F. Hasler_, Aug 02 2016
%C A258374 a(7) <= 2 * 5 * 11 * 89 * 167 * 829 * 7972687 ≈ 1.1e16. - _M. F. Hasler_, Feb 18 2018
%t A258374 (* copy the terms from A002975, assign them equal to 'lst' and then *) Table[ Min@ Select[ lst, PrimeNu@# == n &], {n, 3, 6}]
%Y A258374 Cf. A002975, A258375.
%K A258374 nonn,hard,more
%O A258374 3,1
%A A258374 _Robert G. Wilson v_, May 28 2015