A338357 - OEIS

%I #11 Feb 12 2024 07:28:52

%S 1,2,-1,3,-1,5,-3,7,-6,1,2,11,-10,1,13,-11,1,1,17,-16,1,19,-18,1,2,23,

%T -22,1,2,1,1,29,-28,1,31,-30,1,2,1,1,37,-35,1,1,41,-40,1,43,-42,1,2,

%U 47,-46,1,1,1,1,1,53,-52,1,1,1,2,59,-58,1,61,-59,1,1,1,1,67,-66,1,1,1,71

%N First differences of A283312.

%H N. J. A. Sloane, <a href="/A338357/b338357.txt">Table of n, a(n) for n = 1..10000</a>

%t Module[{nmax = 100, smn = 1}, Differences[Nest[Append[#, If[PrimeQ[Last[#]], 2*Last[#], While[MemberQ[#, ++smn]]; smn]]&, {1}, nmax]]] (* _Paolo Xausa_, Feb 12 2024 *)

%Y Cf. A283312.

%K sign

%O 1,2

%A _N. J. A. Sloane_, Nov 03 2020