OFFSET
1,5
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
n=5, prime(5)=11: (11+1) mod (q+1) = 0 for 3 primes q<11: 2, 3,
and 5, therefore a(5)=3.
MATHEMATICA
Table[Count[Mod[p+1, Prime[Range[PrimePi[p]-1]]+1], 0], {p, Prime[Range[110]]}] (* Harvey P. Dale, Aug 11 2023 *)
PROG
(Haskell)
a084196 n = a084196_list !! (n-1)
a084196_list = f [] a000040_list where
f ps' (p:ps) = length [q | q <- ps', mod (p + 1) (q + 1) == 0] :
f (p : ps') ps where
-- Reinhard Zumkeller, Jan 06 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 18 2003
STATUS
approved