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A157644 Indices of 3's in A090822. 4
9, 18, 28, 37, 41, 45, 46, 56, 65, 75, 84, 88, 92, 93, 97, 107, 116, 126, 135, 139, 143, 144, 154, 163, 173, 182, 186, 190, 191, 195, 199, 203, 204, 208, 212, 216, 217, 218, 219, 229, 238, 248, 257, 261, 265, 266, 276, 285, 295, 304, 308, 312, 313, 317, 327, 336, 346, 355 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There is a group a(i+39) = a(i)+220 for i=1,..,39, then a group a(i+39)=a(i)+220 for i=40,...,78; these correlations become irregular later in the sequence.

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

MATHEMATICA

Clear[a]; reversed = {a[2] = 1, a[1] = 1}; blocs[len_] := Module[{bloc1, par, pos}, bloc1 = Take[reversed, len]; par = Partition[reversed, len]; pos = Position[par, bloc_ /; bloc != bloc1, 1, 1]; If[pos == {}, Length[par], pos[[1, 1]] - 1]]; a[n_] := a[n] = Module[{an}, an = Table[{blocs[len], len}, {len, 1, Quotient[n - 1, 2]}] // Sort // Last // First; PrependTo[reversed, an]; an]; Position[Table[a[n], {n, 1, 355}], 3] // Flatten (* Jean-Fran├žois Alcover, Mar 25 2013 *)

CROSSREFS

Cf. A157334, A107223, A157645.

Sequence in context: A115552 A043322 A071121 * A107223 A194152 A044433

Adjacent sequences:  A157641 A157642 A157643 * A157645 A157646 A157647

KEYWORD

nonn

AUTHOR

Paul Curtz, Mar 03 2009

EXTENSIONS

Extended by R. J. Mathar, Mar 15 2009

STATUS

approved

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Last modified October 1 12:48 EDT 2020. Contains 337443 sequences. (Running on oeis4.)