A180441 First term of four consecutive primes whose average is a prime.

113, 131, 139, 173, 233, 421, 953, 1013, 1021, 1051, 1583, 1747, 1901, 2099, 2423, 2579, 2819, 2939, 3761, 3779, 3931, 4211, 4253, 4451, 4591, 5003, 5861, 5903, 6427, 6691, 6949, 7079, 7481, 7541, 7717, 8263, 8783, 8831, 9127, 9227, 9413, 9923, 10061

Offset: 1

Author

Carmine Suriano, Sep 05 2010

Keywords

• nonn

Examples

			a(5)=233 since (233+239+241+251)/4=964/4=241 is a prime.
		

Crossrefs

Cf. A000040, A122535

Formula

a(n)=[p(n)+p(n+1)+p(n+2)+p(n+3)]/4 a(n) being a prime