A227878 Primes occurring twice in A051701.

3, 19, 41, 43, 71, 83, 101, 109, 151, 167, 199, 227, 229, 257, 281, 283, 311, 313, 349, 383, 401, 443, 461, 463, 487, 503, 571, 601, 617, 641, 643, 677, 727, 757, 829, 857, 859, 881, 883, 911, 937, 941, 971, 1033, 1063, 1091, 1093, 1123, 1187, 1217, 1231

Offset: 1

Author

Reinhard Zumkeller, Oct 25 2013

Keywords

• nonn

Comments

Consider five consecutive primes p1..p5: (p3 is a term of this sequence) iff (p2-p1 > p3-p2 and p5-p4 > p4-p3).

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Programs

Haskell

a227878 n = a227878_list !! (n-1)
a227878_list = f a051701_list where
   f (p:ps@(:p':)) = if p == p' then p : f ps else f ps