A173967 14=2*7;15=3*5;14+15=29, 21=3*7;22=2*11;21+22=43,..

29, 43, 67, 69, 77, 115, 171, 173, 187, 189, 237, 245, 267, 283, 285, 291, 317, 355, 403, 405, 411, 427, 429, 435, 437, 507, 597, 603, 605, 653, 669, 763, 787, 789, 891, 893, 907, 963, 1003, 1029, 1053, 1075, 1085, 1107, 1131, 1245, 1267, 1269, 1389, 1395

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Mathematica

f[n_]:=Last/@FactorInteger[n]=={1, 1}; lst={}; Do[If[f[n], If[f[n+1], AppendTo[lst, 2*n+1]]], {n, 7!}]; lst

Crossrefs

Cf. A173966

Sequence in context: A247896 A162357 A316741 * A004619 A140444 A042969

Adjacent sequences: A173964 A173965 A173966 * A173968 A173969 A173970

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Mar 03 2010, Mar 13 2010

Status

approved