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Records in A171868 (positions).
4

%I #16 Sep 12 2019 15:01:08

%S 1,2,4,9,20,50,147,269,992,1000,4297,76468,97314,445519,1315337,

%T 2594742,3888902,91859035,92411466,1180624310,4501485474,11288114818,

%U 23434425843

%N Records in A171868 (positions).

%H Rémy Sigrist, <a href="/A171887/a171887.txt">C program for A171887</a>

%o (Python)

%o A181391_list, A171887_list, l, r, k = [0, 0], [1], 0, 1, 1

%o for n in range(1, 10**6):

%o ....for m in range(n-1, -1, -1):

%o ........if A181391_list[m] == A181391_list[n]:

%o ............A181391_list.append(n-m)

%o ............break

%o ....else:

%o ........A181391_list.append(0)

%o ........k += 1

%o ........if n-l > r:

%o ............r = n-l

%o ............A171887_list.append(k)

%o ........l = n # _Chai Wah Wu_, Jan 02 2015

%o (C) See Links section.

%Y Cf. A181391, A171865, A171868, A171888.

%K nonn,more

%O 1,2

%A _N. J. A. Sloane_, Oct 18 2010

%E a(12)-a(13) from _Chai Wah Wu_, Jan 02 2015

%E a(14)-a(17) from _Rémy Sigrist_, Jun 11 2019

%E a(18)-a(23) from _Benjamin Chaffin_, Sep 11 2019