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A171887
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Records in A171868 (positions).
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4
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1, 2, 4, 9, 20, 50, 147, 269, 992, 1000, 4297, 76468, 97314, 445519, 1315337, 2594742, 3888902, 91859035, 92411466, 1180624310, 4501485474, 11288114818, 23434425843
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..23.
Rémy Sigrist, C program for A171887
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PROG
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(Python)
A181391_list, A171887_list, l, r, k = [0, 0], [1], 0, 1, 1
for n in range(1, 10**6):
....for m in range(n-1, -1, -1):
........if A181391_list[m] == A181391_list[n]:
............A181391_list.append(n-m)
............break
....else:
........A181391_list.append(0)
........k += 1
........if n-l > r:
............r = n-l
............A171887_list.append(k)
........l = n # Chai Wah Wu, Jan 02 2015
(C) See Links section.
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CROSSREFS
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Cf. A181391, A171865, A171868, A171888.
Sequence in context: A006648 A128496 A134955 * A027881 A002861 A032200
Adjacent sequences: A171884 A171885 A171886 * A171888 A171889 A171890
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KEYWORD
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nonn,more
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AUTHOR
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N. J. A. Sloane, Oct 18 2010
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EXTENSIONS
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a(12)-a(13) from Chai Wah Wu, Jan 02 2015
a(14)-a(17) from Rémy Sigrist, Jun 11 2019
a(18)-a(23) from Benjamin Chaffin, Sep 11 2019
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STATUS
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approved
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