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A180123
Second of three "least, sum, least" self-generating sequences.
3
2, 6, 10, 13, 17, 21, 25, 28, 32, 36, 40, 43, 47, 51, 54, 58, 62, 66, 69, 73, 77, 81, 84, 88, 92, 96, 99, 103, 107, 110, 114, 118, 122, 125, 129, 133, 137, 140, 144, 148, 152, 155, 159, 163, 166, 170, 174, 178, 181, 185, 189, 193, 196, 200, 204, 207, 211, 215, 219
OFFSET
1,1
LINKS
FORMULA
a(n) = least positive integer not yet used;
b(n) = n + a(n);
c(n) = least positive integer not yet used.
EXAMPLE
The three sequences, labeled a,b,c, are
a=(1,4,7,9,...), b=(2,6,10,13,...), c=(3,5,8,11...).
MATHEMATICA
mex[list_, offset_] := NestWhile[# + 1 &, offset, MemberQ[list, #] &];
z = 100; a[1] = 1; b[1] = 1 + a[1];
c[1] = mex[soFar = {a[1], b[1]}, 1];
Do[soFar = Flatten[Join[{soFar, c[n - 1]}]];
a[n] = mex[soFar, c[n - 1]]; b[n] = n + a[n];
soFar = Flatten[Join[{soFar, a[n], b[n]}]];
c[n] = mex[soFar, c[n - 1]], {n, 2, z}]
Map[a, Range[z]](*A180122*)
Map[b, Range[z]](*A180123*)
Map[c, Range[z]](*A180124*)
(* Peter J. C. Moses, Aug 22 2014 *)
A180122 = Map[Floor[(1 + Sqrt[3]) #] - 1 &, Range[200]]
A180123 = A180122 + Range[200]
A180124 = Complement[Range[Last[A180122]], Flatten[{A180122, A180123}]]
(* Peter J. C. Moses, Aug 23 2014 *)
CROSSREFS
Cf. A180122.
Sequence in context: A144031 A190055 A184929 * A247785 A190701 A184918
KEYWORD
nonn
AUTHOR
Clark Kimberling, Aug 11 2010
STATUS
approved