OFFSET
1,2
COMMENTS
For n > 1, a(n) is the least number > a(n-1) such that A001222(a(n) + a(n-1)) = 3.
a(n-1) + a(n) is the least triprime > 2*a(n-1).
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 11 because a(2) = 7, none of 7 + 8 = 15, 7 + 9 = 16 and 7 + 10 = 17 is a triprime, but 7 + 11 = 18 = 2*3^2 is a triprime.
MAPLE
R:= 1: x:= 1:
for i from 1 to 100 do
for y from x+1 while numtheory:-bigomega(x+y) <> 3 do od:
R:= R, y;
x:= y
od:
R;
MATHEMATICA
s = {p = 1}; Do[q = p + 1; While[3 != PrimeOmega[p + q],
q++]; AppendTo[s, p = q], {100}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert Israel, Jul 25 2023
STATUS
approved