OFFSET
1,1
COMMENTS
2 together with A060254.
EXAMPLE
a(1)=2 because 2-1=1=non-semiprime and 2+1=3=non-semiprime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Apr 28 2010
EXTENSIONS
Corrected (233, 239 inserted, 279 and 289 replaced by 379 and 389) by R. J. Mathar, Aug 12 2010
STATUS
approved