OFFSET
1,1
COMMENTS
Conjecture: a(n) exists for any n > 0.
LINKS
Zhi-Wei Sun, Table of n, a(n) for n = 1..100
Zhi-Wei Sun, A new theorem on the prime-counting function, arXiv:1409.5685, 2014.
EXAMPLE
a(4) = 10 since pi(4*10) = 12 divides prime(4) + prime(10) = 7 + 29 = 36.
MATHEMATICA
Do[m=1; Label[aa]; If[m*n>1&&Mod[Prime[m]+Prime[n], PrimePi[m*n]]==0, Print[n, " ", m]; Goto[bb]]; m=m+1; Goto[aa]; Label[bb]; Continue, {n, 1, 60}]
PROG
(Haskell)
a247793_list = 2 : f (zip [2..] $ tail a000040_list) where
f ((x, p) : xps) = m : f xps where
m = head [y | y <- [1..], (p + a000040 y) `mod` a000720 (x * y) == 0]
-- Reinhard Zumkeller, Sep 24 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Sep 23 2014
STATUS
approved