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.

A110227 4-almost primes p * q * r * s relatively prime to p + q + r + s.

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%I A110227 #8 Jan 31 2017 16:46:07
%S A110227 40,54,56,88,90,104,135,136,152,184,189,198,210,225,232,248,250,294,
%T A110227 296,297,306,328,344,350,351,376,390,414,424,441,459,462,472,488,513,
%U A110227 522,536,546,550,568,570,584,621,632,664,686,712,714,735,738,765,776
%N A110227 4-almost primes p * q * r * s relatively prime to p + q + r + s.
%C A110227 p, q, r, s are not necessarily distinct. The converse to this is A110228: 4-almost primes p * q * r * s not relatively prime to p+q+r+s.
%H A110227 Charles R Greathouse IV, <a href="/A110227/b110227.txt">Table of n, a(n) for n = 1..10000</a>
%e A110227 104 is in this sequence because 104 = 2^3 * 13, which is relatively prime to 2 + 2 + 2 + 13 = 19, which is prime.
%o A110227 (PARI) list(lim)=my(v=List()); forprime(p=2,lim\8, forprime(q=2,min(p,lim\4\p), my(pq=p*q); forprime(r=2,min(lim\pq\2,q), my(pqr=pq*r,t); forprime(s=2,min(lim\pqr,r), t=pqr*s; if(gcd(t,p+q+r+s)==1, listput(v,t)))))); Set(v) \\ _Charles R Greathouse IV_, Jan 31 2017
%Y A110227 Cf. A014613, A110187, A110188, A110228, A110229, A110230, A110231, A110232, A110289, A110290, A110296, A110297.
%K A110227 easy,nonn
%O A110227 1,1
%A A110227 _Jonathan Vos Post_, Jul 16 2005
%E A110227 Corrected and extended by _Ray Chandler_, Jul 20 2005