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A077067
Squarefree numbers of form prime + 1.
5
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).
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
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 23 2002
STATUS
approved