OFFSET
1,1
COMMENTS
This rephrases patterns of the form g, *, *, g in four successive entries of A001223, where * denotes arbitrary, not necessarily distinct, values.
The associated indices are n = 4, 9, 12, 17, 19, 20, 21, 24, 38, ...
Each entry is the second next prime after A022887(n). - R. J. Mathar, Jul 12 2013
LINKS
Karl-Heinz Hofmann, Table of n, a(n) for n = 1..10000
EXAMPLE
7 is in the sequence since the gap between the previous two primes (3 and 5) is equal to the gap between the next two primes (11 and 13).
PROG
(Python) from sympy import sieve as p
print([p[k] for k in range(3, 264) if p[k-1] - p[k-2] == p[k+2] - p[k+1]])
# Karl-Heinz Hofmann, May 04 2022
CROSSREFS
KEYWORD
nonn,less
AUTHOR
Juri-Stepan Gerasimov, Jun 30 2013
EXTENSIONS
Corrected by R. J. Mathar, Jul 12 2013
STATUS
approved