A138267 Balanced prime numbers n such that n*(n+1)+1 is a balanced prime.

173, 68099, 76487, 96377, 336593, 488909, 1388381, 2625929, 2757767, 3189287, 3296021, 4057847, 4817399, 5223293, 5803769, 6495509, 6538997, 6569993, 6574769, 6914717, 8928389, 9021323, 9722789, 11439053, 11589467, 12471317, 15061973

Offset

1,1

Links

Table of n, a(n) for n=1..27.

Mathematica

NextPrime[n_Int]:=Module[{k}, k=n+1; While[ !PrimeQ[k], k++ ]; k]; PrevPrime[n_Int]:=Module[{k}, k=n-1; While[ !PrimeQ[k], k-- ]; k]; s=""; For[i=2, i< 10^5*2, p=Prime[i]; If[(Prime[i-1]+Prime[i+1])/2==p, r=p*(p+1)+1; a=PrevPrime[r]; b=NextPrime[r]; If[PrimeQ[r]&&r==(a+b)/2, (*Print[p, ":", a, ", ", b, "; ", r]*)s=s<>ToString[p]<>", "]]; i++ ]; Print[s]

Crossrefs

Cf. A006562.

Sequence in context: A209809 A185707 A185701 * A096709 A180417 A351375

Adjacent sequences: A138264 A138265 A138266 * A138268 A138269 A138270

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 05 2008

Extensions

a(9)-a(27) from Donovan Johnson, Mar 26 2011

Status

approved