OFFSET
1,4
COMMENTS
Zero occurs infinitely often as do the negative numbers.
First occurrence of a(n) beginning with 0: 1, 2, 4, 5, 42, 10, 11, 15, 18, 37, 23, 25, 22, 32, 59, 47, 53, 48, 83, 49, 110, 62, 51, 82, 63, 170, ...,
The first negative term is at n=1473. - T. D. Noe, Apr 09 2009
LINKS
T. D. Noe, Table of n, a(n) for n=1..2000
MATHEMATICA
(Select[1 + 4Range@245, PrimeQ@# &] - Select[ -1 + 4Range@225, PrimeQ@# &] - 2)/4
CROSSREFS
KEYWORD
sign
AUTHOR
Clark Kimberling and Robert G. Wilson v, May 04 2006
STATUS
approved