OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
omega(a(n)-1) + omega(a(n)+1) = omega(a(n)).
EXAMPLE
a(35)=255 because omega(254)+omega(256)=omega(255) or 2+1=3.
MATHEMATICA
Select[Range[5000], PrimeNu[# - 1] + PrimeNu[# + 1] == PrimeNu[ #] &] (* G. C. Greubel, Apr 24 2017 *)
Flatten[Position[Partition[PrimeNu[Range[450]], 3, 1], _?(#[[1]]+#[[3]] == #[[2]]&), 1, Heads->False]]+1 (* Harvey P. Dale, Jul 31 2017 *)
PROG
(PARI) isok(n) = omega(n) == omega(n-1) + omega(n+1); \\ Michel Marcus, Apr 25 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, May 19 2011
EXTENSIONS
a(18) corrected, a(22) added by Charles R Greathouse IV, May 24 2011
STATUS
approved