A343796 a(n) is the number of distinct primes of the form A007504(n) mod p for the first n primes p.

0, 1, 0, 2, 1, 1, 3, 1, 2, 2, 2, 5, 2, 3, 2, 6, 5, 5, 6, 5, 5, 5, 6, 8, 4, 4, 4, 8, 6, 8, 6, 9, 10, 9, 5, 10, 7, 10, 9, 11, 9, 8, 11, 5, 11, 4, 10, 14, 9, 19, 9, 14, 9, 11, 11, 9, 9, 15, 15, 17, 10, 11, 13, 15, 8, 15, 12, 17, 15, 10, 13, 15, 14, 17, 12, 13, 12, 16, 13, 13, 18, 16, 18, 15, 15, 17

Offset

1,4

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(8) = 1 because A007504(8) = 77 and there is only one prime of the form 77 mod p for the first 8 primes p, namely 2 = 77 mod 3 = 77 mod 5.

Maple

N:= 200: # for a(1)..a(N)
P:= [seq(ithprime(i), i=1..N)]:
S:= ListTools:-PartialSums(P):
PS:= convert(P, set):
f:= proc(n)
  nops(map(p -> S[n] mod p, PS[1..n]) intersect PS);
end proc:
map(f, [$1..N]);

Crossrefs

Cf. A007504, A343798.

Sequence in context: A037034 A340056 A229897 * A139462 A236256 A357217

Adjacent sequences: A343793 A343794 A343795 * A343797 A343798 A343799

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Apr 29 2021

Status

approved