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

40, 54, 56, 88, 90, 104, 135, 136, 152, 184, 189, 198, 210, 225, 232, 248, 250, 294, 296, 297, 306, 328, 344, 350, 351, 376, 390, 414, 424, 441, 459, 462, 472, 488, 513, 522, 536, 546, 550, 568, 570, 584, 621, 632, 664, 686, 712, 714, 735, 738, 765, 776

Offset

1,1

Comments

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.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Example

104 is in this sequence because 104 = 2^3 * 13, which is relatively prime to 2 + 2 + 2 + 13 = 19, which is prime.

Prog

(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

Crossrefs

Cf. A014613, A110187, A110188, A110228, A110229, A110230, A110231, A110232, A110289, A110290, A110296, A110297.

Sequence in context: A217729 A255392 A116299 * A108607 A356744 A109730

Adjacent sequences: A110224 A110225 A110226 * A110228 A110229 A110230

Keyword

easy,nonn

Author

Jonathan Vos Post, Jul 16 2005

Extensions

Corrected and extended by Ray Chandler, Jul 20 2005

Status

approved