A283807 - OEIS

A283807

Smallest prime p such that A005117(k+1) - A005117(k-1) = n, where p = A005117(k) for some k.

2, 3, 7, 47, 97, 241, 5051, 204329, 217069, 29002021, 190346677, 3568762019, 221167421, 18725346527

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OFFSET

2,1

LINKS

Table of n, a(n) for n=2..15.

EXAMPLE

2 is in this sequence because A005117(2+1) - A005117(2-1) = 3 - 1 = 2, where A005117(2) = 2 is prime for k = 2.

3 is in this sequence because A005117(3+1) - A005117(3-1) = 5 - 2 = 3, where A005117(3) = 3 is prime for k = 3.

7 is in this sequence because A005117(6+1) - A005117(6-1) = 10 - 6 = 4, where A005117(6) = 7 is prime for k = 6.

47 is in this sequence because A005117(31+1) - A005117(31-1) = 51 - 46 = 5, where A005117(31) = 47 is prime for k = 31.

97 is in this sequence because A005117(61+1) - A005117(61-1) = 101 - 95 = 6, where A005117(61) = 97 is prime for k = 61.

241 is in this sequence because A005117(150+1) - A005117(150-1) = 246 - 239 = 7, where A005117(150) = 241 is prime for k = 150.

5051 is in this sequence because A005117(3071+1) - A005117(3071-1) = 5053 - 5045 = 8, where A005117(3071) = 5051 is prime for k = 3071.

MATHEMATICA

s = Select[Range[10^6], SquareFreeQ]; Table[k = 1; While[Nand[PrimeQ@ Set[p, s[[k]]], s[[k + 1]] - s[[k - 1]] == n], k++]; p, {n, 2, 10}] (* Michael De Vlieger, Mar 18 2017 *)

CROSSREFS

Cf. A000040, A005117 (squarefree numbers), A067535, A070321.

Sequence in context: A090593 A030090 A260298 * A344488 A257108 A274385

Adjacent sequences: A283804 A283805 A283806 * A283808 A283809 A283810

KEYWORD

nonn,more

AUTHOR

Juri-Stepan Gerasimov, Mar 17 2017

EXTENSIONS

a(10) from Michael De Vlieger, Mar 18 2017

a(11)-a(15) from Giovanni Resta, Mar 22 2017

STATUS

approved