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A258050
Position of -n in A258047 after deleting the initial 0.
4
3, 6, 8, 10, 12, 13, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 35, 37, 39, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124
OFFSET
1,1
COMMENTS
A258047 = (0,1,2,-1,3,6,-7,5,-3,7,...). Remove the initial 0 to get (1,2,-1,3,6,-7,5,6,-3,7,...), and note that (1,2,3,4,...) occupy positions 1,2,4,7,..., (as in A258049) and that (-1,-2,-3,...) occupy positions 3,6,8,... (as in A258050).
LINKS
MATHEMATICA
{a, f} = {{1}, {0}}; Do[tmp = {#, # - Last[a]} &[Min[Complement[#, Intersection[a, #]]&[Last[a] + Complement[#, Intersection[f, #]] &[Range[2 - Last[a], -1]]]]];
If[! IntegerQ[tmp[[1]]], tmp = {Last[a] + #, #} &[NestWhile[# + 1 &, 1, ! (! MemberQ[f, #] && ! MemberQ[a, Last[a] - #]) &]]];
AppendTo[a, tmp[[1]]]; AppendTo[f, tmp[[2]]], {500}];
-1 + Flatten[Position[Sign[f], 1]] (* A258049 *)
-1 + Flatten[Position[Sign[f], -1]] (* A258050 *) (* Peter J. C. Moses, May 14 2015 *)
CROSSREFS
Cf. A258047, A258049 (complement).
Sequence in context: A108769 A286754 A186387 * A185547 A112234 A189467
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 05 2015
STATUS
approved