A085904 Numbers n such that n, n+1 and n+2 are highly composite numbers (2), i.e., all prime divisors <= 7 (A002473).

1, 2, 3, 4, 5, 6, 7, 8, 14, 48

Offset

1,2

Comments

No more terms < 3*10^7. Probably no more terms. - David Wasserman, Feb 10 2005

No more terms < 2^180. - Donovan Johnson, Oct 10 2012

There are no further terms: see A003032 (and maybe A002072). - Don Reble, Mar 14 2019

Links

Table of n, a(n) for n=1..10.

Example

48 is a member as 48, 49 and 50 have all prime divisors <= 7.

Prog

(PARI) mx=2^180+2; v=vector(4607193); c=0; for(e1=0, 180, x1=2^e1; for(e2=0, 113, x2=x1*3^e2; if(x2>mx, next(2)); for(e3=0, 77, x3=x2*5^e3; if(x3>mx, next(2)); for(e4=0, 64, x4=x3*7^e4; if(x4>mx, next(2)); c++; v[c]=x4)))); v=vecsort(v); for(i=1, 4607191, if(v[i+1]-v[i]==1, if(v[i+2]-v[i]==2, print1(v[i] ", ")))) /* Donovan Johnson, Oct 10 2012 */

Crossrefs

Cf. A002473.

Sequence in context: A088416 A057913 A245802 * A032997 A319724 A097546

Adjacent sequences: A085901 A085902 A085903 * A085905 A085906 A085907

Keyword

nonn,fini,full

Author

Amarnath Murthy, Jul 09 2003

Extensions

Offset corrected and missing term added by Donovan Johnson, Oct 10 2012

Status

approved