A079095 Squarefree numbers of the form (prime(k)+1)*(prime(k+1)+1)/4.

3, 6, 42, 399, 462, 930, 1054, 3135, 4830, 6478, 13110, 19599, 20022, 24963, 26394, 35530, 38805, 39999, 41205, 44310, 52899, 71002, 74254, 81510, 94863, 95790, 103362, 109230, 111547, 114243, 135790, 144399, 146685, 157206, 166866, 183183

Offset: 1

Author

Reinhard Zumkeller, Dec 22 2002

Keywords

• nonn

Examples

			(A000040(12)+1)*(A000040(12+1)+1)/4 = (37+1)*(41+1)/4 = 399 = 3*7*19, therefore 399 is a term.
		

Links

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

Crossrefs

Intersection of A005117 and A079079.

Cf. A000040, A008966, A079093.

Programs

Haskell

a079095 n = a079095_list !! (n-1)
a079095_list = filter ((== 1) . a008966) a079079_list
-- Reinhard Zumkeller, Oct 09 2012

Mathematica

With[{p = Prime[Range[150]]}, Select[(Most[p]+1) * (Rest[p]+1) / 4, SquareFreeQ]] (* Amiram Eldar, Apr 06 2025 *)

Formula

A008966(a(n)) = 1.