OFFSET
1,1
COMMENTS
In Ulam's lattice there are 8 numbers around any number. The sequence is similar to A136626 with an increment of 1 for any prime position.
EXAMPLE
Numbers around 13 are 3, 12, 29, 30, 31, 32, 33, 14 -> 3, 29, 31 and 13 itself are primes, so a(13)=4.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paolo P. Lava and Giorgio Balzarotti, Jan 14 2008
EXTENSIONS
Offset 1 per example and correction for a(32) by Kevin Ryde, Jul 04 2020
STATUS
approved