A136151 Composites n with exactly two distinct prime divisors and of the form n=1+(any prime).

6, 12, 14, 18, 20, 24, 38, 44, 48, 54, 62, 68, 72, 74, 80, 98, 104, 108, 152, 158, 164, 192, 194, 200, 212, 224, 242, 272, 278, 284, 314, 332, 338, 368, 384, 398, 422, 432, 458, 464, 488, 500, 524, 542, 548, 578, 608, 614, 632, 648, 662, 674, 692, 734, 752, 758

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

A008864 INTERSECT A007774. - R. J. Mathar, Feb 01 2008

Maple

isA136151 := proc(n) if isprime(n-1) then if nops(numtheory[factorset](n)) =2 then true; else false ; fi ; else false ; fi ; end: for i from 1 to 200 do n := ithprime(i)+1 ; if isA136151( n) then printf("%d, ", n) ; fi ; od: # R. J. Mathar, Feb 01 2008

Mathematica

Select[Range[800], PrimeNu[#]==2&&PrimeQ[#-1]&] (* Harvey P. Dale, Jun 22 2018 *)

Crossrefs

Cf. A136152, A136153, A136154, A136155.

Sequence in context: A336549 A136155 A315599 * A315600 A056774 A315601

Adjacent sequences: A136148 A136149 A136150 * A136152 A136153 A136154

Keyword

easy,nonn

Author

Enoch Haga, Dec 16 2007

Extensions

Edited by R. J. Mathar, Feb 01 2008

Status

approved