OFFSET
1,2
COMMENTS
For a guide to related sequences, see A377609.
EXAMPLE
Starting with prime(1) = 2, we have 2*2+5 = 9; the chain (2,9) has 1 prime and 1 composite. So a(1) = 2-1 = 1.
MATHEMATICA
chain[{start_, u_, v_}] := NestWhile[Append[#, u*Last[#] + v] &, {start}, !
Count[#, _?PrimeQ] == Count[#, _?(! PrimeQ[#] &)] &];
chain[{Prime[1], 2, 5}]
Map[Length[chain[{Prime[#], 2, 5}]] &, Range[100]] - 1
(* Peter J. C. Moses Oct 31 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Nov 13 2024
STATUS
approved