OFFSET
1,1
COMMENTS
Probably for all n>1 and also for all average s there are at least an average n*s. Note that this is equivalent to the Twin Prime Conjecture. Verified n to 10^7. First consecutive averages: 4 to 34260.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
MATHEMATICA
t=Select[Table[Prime[n] + 1, {n, 10^4}], PrimeQ[#1 + 1] & ]; Table[s:=t[[m]]; m=1; While[!PrimeQ[n*s-1] || !PrimeQ[n*s+1], m++]; s, {n, 1, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Manuel Valdivia, Mar 12 2012
STATUS
approved