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

1,1

Comments

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

Links

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

Example

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.

Mathematica

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

Prog

(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

Crossrefs

Cf. A254863.

Sequence in context: A123221 A197032 A321781 * A340641 A322235 A346477

Adjacent sequences: A254859 A254860 A254861 * A254863 A254864 A254865

Keyword

nonn

Author

Zak Seidov, Feb 09 2015

Status

approved