A254862 Least prime p such that p + nextprime(p) is a multiple of n.

2, 3, 5, 3, 2, 5, 19, 3, 7, 13, 97, 5, 23, 19, 13, 53, 31, 7, 73, 29, 19, 97, 67, 11, 47, 23, 79, 41, 347, 13, 89, 61, 97, 31, 103, 17, 109, 73, 37, 59, 199, 19, 83, 151, 43, 67, 281, 71, 439, 47, 101, 23, 631, 79, 163, 53, 227, 347, 233, 29, 607, 89, 313, 61, 193, 97, 131, 31, 67, 103, 421, 71

Offset: 1

Author

Zak Seidov, Feb 09 2015

Keywords

• nonn

Comments

for k=1..10, a(1000*k) = 2999, 2999, 2999, 21997, 12497, 2999, 10499, 51991, 4493, 29989.

Examples

			2+3=5=1*5, 3+5=8=2*4, 5+7=12=3*4, 3+5=8=4*1, 2+3=5=5*1, 5+7=12=6*2, 19+23=42=7*6, 3+5=8=8*1, 7+11=18=9*2, 13+17=30=10*3.
		

Links

• Ivan Neretin, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A254863.

Programs

Mathematica

  s={};Do[p=2;q=3;While[Mod[p+q,n]>0,p=q;q=NextPrime[q]];AppendTo[s,p],{n,50}];s

PARI

s=[];for(n=1,50,p=2;q=3;while((p+q)%n>0,p=q;q=nextprime(q+1));s=concat(s,p));s