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A171887 Records in A171868 (positions).

%I A171887 #21 May 22 2025 21:00:26
%S A171887 1,2,4,9,20,50,147,269,992,1000,4297,76468,97314,445519,1315337,
%T A171887 2594742,3888902,91859035,92411466,1180624310,4501485474,11288114818,
%U A171887 23434425843
%N A171887 Records in A171868 (positions).
%H A171887 Rémy Sigrist, <a href="/A171887/a171887.txt">C program for A171887</a>
%o A171887 (Python)
%o A171887 A181391_list, A171887_list, l, r, k = [0, 0], [1], 0, 1, 1
%o A171887 for n in range(1, 10**6):
%o A171887     for m in range(n-1, -1, -1):
%o A171887         if A181391_list[m] == A181391_list[n]:
%o A171887             A181391_list.append(n-m)
%o A171887             break
%o A171887     else:
%o A171887         A181391_list.append(0)
%o A171887         k += 1
%o A171887         if n-l > r:
%o A171887             r = n-l
%o A171887             A171887_list.append(k)
%o A171887         l = n # _Chai Wah Wu_, Jan 02 2015
%o A171887 (C) // See Links section.
%Y A171887 Cf. A181391, A171865, A171868, A171888.
%K A171887 nonn,more
%O A171887 1,2
%A A171887 _N. J. A. Sloane_, Oct 18 2010
%E A171887 a(12)-a(13) from _Chai Wah Wu_, Jan 02 2015
%E A171887 a(14)-a(17) from _Rémy Sigrist_, Jun 11 2019
%E A171887 a(18)-a(23) from _Benjamin Chaffin_, Sep 11 2019