A141831 - OEIS

A141831

Primes not in sequence A141830.

7, 19, 23, 31, 43, 47, 53, 67, 73, 79, 83, 89, 103, 113, 127, 131, 139, 151, 157, 163, 167, 173, 181, 199, 211, 223, 233, 241, 251, 257, 263, 271, 283, 293, 307, 317, 331, 337, 353, 359, 367, 373, 379, 383, 389, 401, 409, 421, 433, 439, 443, 449, 463, 467, 479

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OFFSET

1,1

COMMENTS

This sequence gives the primes p where not every positive integer k <= q-p divides p-1, where q is the prime immediately after p.

LINKS

Table of n, a(n) for n=1..55.

MAPLE

isA141831 := proc(p) local q, d ; if isprime(p) then q := nextprime(p) ; for d from 1 to q-p do if (p+d-1) mod d <> 0 then RETURN(true) ; fi; od: RETURN(false) ; else false; fi; end: for i from 1 to 300 do p := ithprime(i) ; if isA141831(p) then printf("%d, ", p) ; fi; od: # R. J. Mathar, Aug 08 2008

MATHEMATICA

fQ[n_] := Block[{p = n, q = NextPrime@ n}, Union[IntegerQ /@ (Range[p, q - 1]/Range[q - p])][[1]]]; Select[ Prime@ Range@ 92, !fQ@ # &] (* Robert G. Wilson v *)

CROSSREFS

Cf. A141829, A141830.

Sequence in context: A129812 A353046 A032680 * A379307 A176182 A292349

Adjacent sequences: A141828 A141829 A141830 * A141832 A141833 A141834

KEYWORD

nonn

AUTHOR

Leroy Quet, Jul 09 2008

EXTENSIONS

Extended beyond 53 by R. J. Mathar, Aug 08 2008

STATUS

approved