A345363 Composite numbers that are the exact average of three consecutive primes.

511, 537, 999, 1073, 1239, 1461, 1501, 1541, 1763, 1773, 1899, 1917, 2071, 2181, 2401, 2409, 2449, 3059, 3069, 3179, 3201, 3509, 3807, 4081, 4101, 4179, 4387, 4399, 4437, 4467, 4559, 4607, 4681, 4705, 4879, 5089, 5211, 5257, 5271, 5373, 5429, 5757, 5829, 6415, 6621, 6671

Offset: 1

Author

Tanya Khovanova, Jun 16 2021

Keywords

• nonn

Examples

			511 is composite and the average of the consecutive primes 503, 509 and 521. Thus, 511 is in the sequence.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A242218 (subsequence of semiprimes).

Programs

Mathematica

Select[Table[(Prime[n] + Prime[n + 1] + Prime[n + 2])/3, {n, 2000}], IntegerQ[#] && ! PrimeQ[#] &]
Select[Mean/@Partition[Prime[Range[1000]],3,1],IntegerQ[#]&&CompositeQ[#]&] (* Harvey P. Dale, Feb 01 2025 *)