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URL: https://oeis.org/A372181

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A372181
a(n) is the smallest number whose symmetric representation of sigma consists of n copies of unimodal pattern 121 (separated by 0's if n > 1).
2
6, 78, 1014, 12246, 171366, 1922622, 28960854, 300014754, 4174476774
OFFSET
1,1
COMMENTS
This sequence is infinite (see A372180).
EXAMPLE
a(2) = 78 is the smallest number whose symmetric representations of sigma has unimodal pattern 1210121.
a(4) = 12246 is the smallest number whose symmetric representations of sigma has unimodal pattern 121012101210121.
MATHEMATICA
(* function seqQ[ ] is defined in A372180 *)
smallest[s_, m_] := NestWhile[#+1&, s, !seqQ[#, m]&]
a372181[n_] := Rest[FoldList[smallest[#1, #2]&, 1, Range[n]]]
a372181[9] (* long computation time *)
CROSSREFS
Row 2 of A367377.
Row 1 of A372180.
Cf. A237593.
Sequence in context: A186663 A069670 A074112 * A197103 A345360 A208473
KEYWORD
nonn,more
AUTHOR
Hartmut F. W. Hoft, Apr 21 2024
STATUS
approved