A077067 Squarefree numbers of form prime + 1.

3, 6, 14, 30, 38, 42, 62, 74, 102, 110, 114, 138, 158, 174, 182, 194, 230, 258, 278, 282, 314, 318, 354, 374, 390, 398, 402, 410, 422, 434, 458, 462, 510, 542, 570, 602, 614, 618, 642, 654, 662, 674, 678, 710, 734, 758, 762, 770, 798, 822, 830, 854, 858, 878

Offset

1,1

Comments

A077066(a(n)) = a(n).

Links

Table of n, a(n) for n=1..54.

Formula

a(n) = A049097(n)+1. - Zak Seidov, Aug 15 2006

Example

A005117(28)=42=2*3*7 is a term as 42=A000040(13)+1=41+1.

Mathematica

Select[Prime[Range[200]]+1, SquareFreeQ] (* Harvey P. Dale, Aug 20 2017 *)

Prog

(PARI) isok(n) = issquarefree(n) && isprime(n-1); \\ Michel Marcus, Mar 22 2016
(PARI) lista(nn) = forprime(p=2, nn, if (issquarefree(p+1), print1(p+1, ", "))); \\ Michel Marcus, Mar 22 2016

Crossrefs

Cf. A008864, A005117, A000040, A077064, A049097.

Sequence in context: A084174 A036658 A307457 * A083797 A308580 A192672

Adjacent sequences: A077064 A077065 A077066 * A077068 A077069 A077070

Keyword

nonn

Author

Reinhard Zumkeller, Oct 23 2002

Status

approved