Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #5 Jul 10 2020 13:04:02
%S 1,0,1,-1,0,2,-1,-1,0,3,-3,0,0,1,1,-2,0,4,-4,0,0,0,1,-1,0,0,5,-5,0,0,
%T 0,3,-3,0,0,0,0,0,0,0,1,1,-2,6,-6,0,0,0,0,0,0,0,1,-1,0,0,0,0,0,0,0,0,
%U 0,0,0,0,0,4,-4,7,-7,0,0,0,0,0,0,1,-1,0,0,0,0,0,0,2,-2,0,0,0,1,-1,0,0
%N First differences of exponents of consecutive prime powers.
%C a(n) = A025474(n+1) - A025474(n).
%t Join[{1},Differences[FactorInteger[#][[1,2]]&/@Select[Range[ 400], PrimePowerQ]]] (* _Harvey P. Dale_, Jul 10 2020 *)
%Y Cf. A088233, A000961, A057820.
%K sign
%O 1,6
%A _Reinhard Zumkeller_, Sep 25 2003