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A387075 First differences of A386482.

%I A387075 #7 Aug 16 2025 01:13:57
%S A387075 1,2,2,-3,6,3,-2,-2,6,-7,14,-3,-2,4,-5,-10,20,5,-2,-2,-2,-2,-11,22,-6,
%T A387075 9,-2,-2,6,-19,38,-3,-2,-2,-2,-2,-2,-2,-2,-5,10,-6,-26,52,-5,-2,-2,-7,
%U A387075 14,-12,-34,51,-2,-2,-2,-31,62,-3,-2,-2,-2,-2,-2,-2,-2,-2
%N A387075 First differences of A386482.
%H A387075 Michael De Vlieger, <a href="/A387075/b387075.txt">Table of n, a(n) for n = 1..10000</a>
%H A387075 Michael De Vlieger, <a href="/A387075/a387075.png">Logarithmic scatterplot of log_10 |a(n)|</a>, n = 1..2^20, showing negative values in red and positive in green.
%t A387075 Block[{c, j, k, m, p, r, nn},
%t A387075   nn = 120; c[_] := False; m[_] := 1; j = 2; c[1] = c[2] = True; r = 0;
%t A387075   {1, 2}~Join~Monitor[Reap[Do[
%t A387075     If[PrimePowerQ[j],
%t A387075       Set[{p, k, m}, {#1, #1^(#2 - 1), #1^(#2 - 1)}] & @@
%t A387075         FactorInteger[j][[1]]; While[And[c[k*p], k != 0], k--];
%t A387075         If[k == 0, k = m; While[c[k*p], k++]]; k *= p,
%t A387075       k = j - 1; While[And[Or[c[k], CoprimeQ[j, k]], k != 1], k--];
%t A387075         If[k == 1, k += j; While[Or[c[k], CoprimeQ[j, k] ], k++] ] ];
%t A387075     Sow[k - j]; Set[{c[k], j}, {True, k}], {n, 3, nn}] ][[-1, 1]], n] ]
%Y A387075 Cf. A386482.
%K A387075 sign
%O A387075 1,2
%A A387075 _Michael De Vlieger_, Aug 15 2025