A084198 - OEIS

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A084198

Primes p such that there exists exactly one prime q<p with q+1 dividing p+1.

5, 7, 19, 43, 67, 97, 163, 181, 211, 283, 331, 349, 523, 547, 601, 691, 787, 853, 907, 937, 1021, 1051, 1123, 1171, 1429, 1531, 1549, 1723, 1777, 1867, 2011, 2029, 2053, 2083, 2113, 2251, 2281, 2347, 2371, 2467, 2521, 2707, 2731, 2749, 2803, 2971, 3067

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

A084196(A049084(a(n)))=1.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

MATHEMATICA

pdQ[n_]:=Module[{prs=Prime[Range[500]], p1}, p1=Select[prs, #<n&]+1; Count[ p1, _?(Divisible[n+1, #]&)]==1]; Select[Prime[Range[500]], pdQ] (* Harvey P. Dale, Dec 24 2013 *)

PROG

(Haskell)

a084198 n = a084198_list !! (n-1)

a084198_list = map a000040 $ filter ((== 1) . a084196) [1..]

-- Reinhard Zumkeller, Jan 06 2014

CROSSREFS

Sequence in context: A106987 A342738 A321510 * A036061 A288608 A079361

Adjacent sequences: A084195 A084196 A084197 * A084199 A084200 A084201

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 18 2003

EXTENSIONS

Corrected by T. D. Noe, Oct 25 2006

STATUS

approved