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A074275
Positions of occurrences of 1,2,2,1,2 in the Kolakoski sequence A000002.
3
7, 17, 34, 43, 52, 61, 73, 79, 88, 98, 106, 125, 134, 143, 149, 152, 161, 170, 179, 196, 202, 211, 230, 233, 248, 257, 260, 277, 286, 295, 298, 304, 313, 323, 331, 340, 346, 358, 367, 373, 376, 391, 394, 403, 411, 421, 430, 433, 448, 451, 457, 466, 476, 493
OFFSET
1,1
LINKS
EXAMPLE
The Kolakoski sequence begins 1,2,2,1,1,2,1,2,2,1,2,2,1,1,2,1,1,1,2,2,1,2,..., so 1,2,2,1,2 occurs at positions 7 and 17.
MATHEMATICA
a2 = {1, 2, 2}; Do[ a2 = Join[a2, {1 + Mod[n - 1, 2]}], {n, 3, 400}, {i, 1, a2[[n]]}]; a2 //. {a___, 1, 2, 2, 1, 2, b___} :> {a, 0, 2, 2, 1, 2, b} // Flatten // Position[#, 0] & // Flatten (* Jean-François Alcover, Jun 18 2013 *)
CROSSREFS
Sequence in context: A301695 A301725 A278920 * A051411 A195016 A296553
KEYWORD
nonn,easy
AUTHOR
Jon Perry, Sep 21 2002
EXTENSIONS
Extended and offset corrected by Nathaniel Johnston, May 02 2011
STATUS
approved