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.

A110231 6-almost primes p * q * r * s * t * u relatively prime to p+q+r+s+t+u.

Original entry on oeis.org

96, 224, 352, 360, 416, 486, 504, 544, 600, 608, 736, 792, 810, 928, 936, 992, 1000, 1176, 1184, 1224, 1312, 1368, 1376, 1400, 1504, 1656, 1696, 1701, 1782, 1888, 1890, 1952, 2025, 2040, 2088, 2144, 2184, 2200, 2232, 2250, 2272, 2336, 2528, 2600, 2646
Offset: 1

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Author

Jonathan Vos Post, Jul 17 2005

Keywords

Comments

p, q, r, s, t, u are not necessarily distinct. The converse to this is A110232: 6-almost primes p * q * r * s * t * u which are not relatively prime to p+q+r+s+t+u. A046306 is the 6-almost primes.

Examples

			96 is an element of this sequence because 96 = 2^5 * 3, the sum of whose prime factors is 2 + 2 + 2 + 2 + 2 + 3 = 13, which has no prime factors in common with 96.
		

Crossrefs

Programs

  • PARI
    list(lim)=my(v=List()); forprime(p=2, lim\32, forprime(q=2, min(p, lim\16\p), my(pq=p*q); forprime(r=2, min(lim\pq\8, q), my(pqr=pq*r); forprime(s=2, min(lim\pqr\4, r), my(pqrs=pqr*s); forprime(t=2,min(lim\pqrs\2,s), my(pqrst=pqrs*t,n); forprime(u=2,min(lim\pqrst,t), n=pqrst*u; if(gcd(n, p+q+r+s+t+u)==1, listput(v, n)))))))); Set(v) \\ Charles R Greathouse IV, Jan 31 2017

Extensions

Extended by Ray Chandler, Jul 20 2005