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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).

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%I A372181 #15 Apr 28 2024 18:59:44
%S A372181 6,78,1014,12246,171366,1922622,28960854,300014754,4174476774
%N 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).
%C A372181 This sequence is infinite (see A372180).
%e A372181 a(2) = 78 is the smallest number whose symmetric representations of sigma has unimodal pattern 1210121.
%e A372181 a(4) = 12246 is the smallest number whose symmetric representations of sigma has unimodal pattern 121012101210121.
%t A372181 (* function seqQ[ ] is defined in A372180 *)
%t A372181 smallest[s_, m_] := NestWhile[#+1&, s, !seqQ[#, m]&]
%t A372181 a372181[n_] := Rest[FoldList[smallest[#1, #2]&, 1, Range[n]]]
%t A372181 a372181[9] (* long computation time *)
%Y A372181 Row 2 of A367377.
%Y A372181 Row 1 of A372180.
%Y A372181 Cf. A237593.
%K A372181 nonn,more
%O A372181 1,1
%A A372181 _Hartmut F. W. Hoft_, Apr 21 2024