login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A275108 Record gaps between numbers that are either primes or semiprimes. 4
1, 2, 3, 4, 6, 10, 11, 12, 16, 18, 19, 22, 24, 25, 26, 30, 32, 34, 36, 40, 42, 44, 51, 56, 64, 66, 70, 71, 78, 81, 85, 86, 91, 106, 110, 112, 128 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = A275014(n) - A275013(n).
EXAMPLE
a(5) = 6 because the next prime or semiprime after 241 is 247, and that is a record gap of size 6.
PROG
(PARI) checkrange(a, b, r)=while(b-a>r, forstep(n=a+r, a+1, -1, if(bigomega(n)<3, a=n; next(2))); for(n=a+r+1, b, if(bigomega(n)<3, return([a, n])))); 0
print1(1); p=5; r=1; forprime(q=7, 1e9, if(q-p<=r, p=q; next); t=checkrange(p, q, r); while(t, print1(", "t[2]-t[1]); t=checkrange(t[2], q, r=t[2]-t[1])); p=q) \\ Charles R Greathouse IV, Nov 19 2016
CROSSREFS
Sequence in context: A047417 A066936 A067027 * A005457 A005453 A180242
KEYWORD
nonn,more
AUTHOR
Bobby Jacobs, Nov 13 2016
EXTENSIONS
a(32)-a(37) from Giovanni Resta, Apr 25 2020
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 04:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)