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.

A272044 Numbers n such that n and n^2+1 have the same number of prime factors (including multiplicities).

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%I A272044 #17 Apr 20 2016 06:24:57
%S A272044 2,9,15,18,22,25,27,34,35,39,46,49,51,58,62,63,65,69,70,75,85,86,95,
%T A272044 98,105,106,121,125,132,138,141,145,147,148,153,158,159,166,169,172,
%U A272044 174,178,194,201,202,205,209,212,214,219,221,226,254,262,274,282,285,289,298,299
%N A272044 Numbers n such that n and n^2+1 have the same number of prime factors (including multiplicities).
%H A272044 Charles R Greathouse IV, <a href="/A272044/b272044.txt">Table of n, a(n) for n = 1..10000</a>
%F A272044 Numbers n such that bigomega(n) = bigomega(n^2+1).
%p A272044 with(numtheory): A272044:=n->`if`(bigomega(n)=bigomega(n^2+1), n, NULL): seq(A272044(n), n=1..500); # _Wesley Ivan Hurt_, Apr 19 2016
%t A272044 Select[Range@ 300, PrimeOmega[#^2 + 1] == PrimeOmega@ # &] (* _Michael De Vlieger_, Apr 19 2016 *)
%o A272044 (PARI) is(n)=bigomega(n)==bigomega(n^2+1) \\ _Charles R Greathouse IV_, Apr 18 2016
%Y A272044 Cf. A001222 (bigomega), A193330.
%K A272044 nonn
%O A272044 1,1
%A A272044 _Benjamin Przybocki_, Apr 18 2016