A274360 Numbers n such that n and n+1 both have 18 divisors.

6075, 23275, 25856, 26900, 33524, 45324, 46475, 61299, 61347, 77076, 82075, 93924, 96236, 107775, 111924, 117324, 118700, 133524, 137924, 155771, 209524, 210176, 219275, 229275, 230643, 234099, 257724, 258475, 272924, 275300, 278271, 312987, 325899, 332667, 348524

Offset

1,1

Links

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

Prog

(PARI) is(n)=numdiv(n)==18 && numdiv(n+1)==18
(PARI) list(lim)=my(v=List()); forprime(p=2, sqrtint(lim\12), forprime(q=2, sqrtint(lim\p^2\2), if(p==q, next); my(pq2=(p*q)^2); forprime(r=2, lim\pq2, if(p==r || q==r, next); t=pq2*r; if(numdiv(t-1)==18, listput(v, t-1)); if(numdiv(t+1)==18, listput(v, t))))); Set(v)

Crossrefs

Intersection of A005237 and A030636.

Cf. A000005, A274357.

Sequence in context: A241245 A260105 A084804 * A025515 A031576 A204966

Adjacent sequences: A274357 A274358 A274359 * A274361 A274362 A274363

Keyword

nonn

Author

Charles R Greathouse IV, Jun 19 2016

Status

approved