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A229120 Inverse of permutation A229119. 2
1, 3, 2, 7, 6, 5, 15, 14, 4, 13, 10, 31, 30, 12, 29, 9, 26, 21, 63, 62, 28, 61, 8, 25, 58, 11, 18, 53, 42, 127, 126, 60, 125, 24, 57, 122, 17, 27, 50, 117, 22, 37, 106, 85, 255, 254, 124, 253, 56, 121, 250, 16, 49, 59, 114, 245, 19, 34, 54, 101, 234, 20, 45, 74, 213, 170, 511, 510, 252, 509, 120, 249, 506, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Defines an infinite permutation on the integers, containing cycles of infinite length, but with an inverse (A229119) that can be generated.

The least integer producing an infinite cycle is n=4 : {4, 7, 15, 29, 42, 37, 17, 26, 11, 10, 13, 30, 127, 77, 242, 266, 173, 205, 2034, 6474, ...

LINKS

Table of n, a(n) for n=1..74.

Link to permutations section in OEIS

EXAMPLE

See A229119.

MATHEMATICA

<< Combinatorica`; unrankpartition[n_Integer, k_Integer] := Block[{ove, res, qq, zz, mem}, ove=PartitionsP[n]-k; res={}; While[n-Tr[res]>0, qq=0; zz=0; While[(mem=NumberOfPartitions[n-Tr[res], qq + 1]) <= ove, zz = mem; qq++]; AppendTo[res, qq + 1]; ove = ove-zz]; res] /; k <= PartitionsP[n] && k > 0; unrankpartition[n_Integer, All]:=Block[{k=1, z}, While[( z=Tr[PartitionsP[Range@k]])<n, k++]; unrankpartition[k, PartitionsP[k]+n-z]]; par2int[par_?PartitionQ]:=Block[{t3, t4, t5}, t3=Differences[Prepend[Reverse[par], 0]]; t4=Reverse@MapAt[#-1&, 1+t3, 1]; t5=Flatten[Table[Mod[k, 2]+0*Range[t4[[k]]], {k, Length[t4]}]]; FromDigits[t5, 2]]; b = Table[par2int@unrankpartition[n, All], {n, 138}]

CROSSREFS

Cf. A226062.

Sequence in context: A267107 A126316 A101224 * A255067 A139285 A080398

Adjacent sequences:  A229117 A229118 A229119 * A229121 A229122 A229123

KEYWORD

nonn

AUTHOR

Wouter Meeussen, Sep 14 2013

STATUS

approved

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Last modified June 4 07:23 EDT 2020. Contains 334822 sequences. (Running on oeis4.)