1,1

Table of n, a(n) for n=1..42.

a(n) + nextprime(a(n)) = A000217(A175132(n)).

tri[n_] := IntegerQ[Sqrt[1 + 8 n]]; t = {}; p1 = 2; While[Length[t] < 50, p2 = NextPrime[p1]; If[tri[p1 + p2], AppendTo[t, p1]]; p1 = p2]; t (* T. D. Noe, May 28 2013 *)

Cf. A175132 (numbers n such that sum of two consecutive primes is triangular(n)).

Cf. A181902 and A154634 (average of two consecutive primes is a triangular number).

Cf. A075190 and A225195 (average of two consecutive primes is a square).

Cf. A074924 and A061275 (sum of two consecutive primes is a square).

Sequence in context: A165493 A295338 A059425 * A146328 A161549 A269788

Adjacent sequences: A225074 A225075 A225076 * A225078 A225079 A225080

nonn

Alex Ratushnyak, May 28 2013

approved