A115394 List of triples of semiprimes: each three numbers are consecutive semiprimes.

33, 34, 35, 85, 86, 87, 93, 94, 95, 121, 122, 123, 141, 142, 143, 201, 202, 203, 213, 214, 215, 217, 218, 219, 301, 302, 303, 393, 394, 395, 445, 446, 447, 633, 634, 635, 697, 698, 699, 841, 842, 843, 921, 922, 923, 1041, 1042, 1043, 1137, 1138, 1139, 1261

Offset: 1

Author

Zak Seidov, Mar 08 2006

Keywords

• nonn

Crossrefs

Cf. A056809, A086005, A086006.

Programs

Mathematica

Flatten[Select[Partition[Union[Times@@@Tuples[Prime[Range[150]],{2}]],3,1],#[[3]]-#[[2]]==#[[2]]-#[[1]]==1&]]  (* Harvey P. Dale, Jan 22 2011 *)

Formula

a(3n-2) = A056809(n), a(3n-1) = A086005(n), a(3n) = A086005(n) + 1 = 2*A086006(n) + 1, n=1,2,...