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Search: id:A094017
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| A094017 |
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Least number k whose binary representation is not contained in that of n!. |
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+0
2
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| 2, 3, 4, 5, 5, 7, 10, 10, 7, 9, 7, 5, 13, 15, 15, 15, 17, 17, 15, 17, 18, 17, 29, 21, 17, 28, 20, 31, 21, 36, 15, 15, 35, 42, 41, 35, 33, 22, 45, 22, 36, 46, 50, 41, 37, 33, 21, 40, 38, 31, 66, 33, 60, 45, 51, 42, 42, 60, 35, 38, 63, 65, 75, 75, 39, 71, 36, 75, 67, 74, 67, 68, 78
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sum_{n=1..3000} a(n) = 4179226. The average value of a(n)/n -> 0.93+ and except for some initial terms, <212, .90 < a(n)/n < .95. But there is graphical evidence that this value may increase.
a(n)=n only for 5, 13, 15, 17, 513, 517, 1041, 1538, 2138, n =< 2500. a(n)=n+1 for n=1, 2, 3, 4, 6, 14, 134, 137, 155, 169, 216, 313, 530, 1035 & 2402.
a(n)>=3n/2 for n=1, 2, 334, 335, 2693 & 2739.
a(n)=<n/2 for n=12, 31, 32, 47, 122, 142, 152, 188, 303, 378, 443, 548, 598, 1319, 1354, 1420, 2127, 2137, 2223, 2230, 2368, 2433, 2571.
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EXAMPLE
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a(7)=10 because 7! = 1001110110000_b and 1_b, 10_b, 11_b, 100_b, 101_b,
110_b, 111_b, 1000_b & 1001_b are substrings, but 10_d = 1010_b is not a substring.
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MATHEMATICA
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f[n_] := ToString[ FromDigits[ IntegerDigits[n, 2]]]; g[n_] := g[n] = Block[{k = 1, s = f[n! ]}, While[ StringPosition[ s, f[k]] != {}, k++ ]; k]; Table[ g[n], {n, 75}]
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CROSSREFS
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Cf. A092601.
Sequence in context: A136623 A031218 A092762 this_sequence A017844 A011156 A037849
Adjacent sequences: A094014 A094015 A094016 this_sequence A094018 A094019 A094020
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 21 2004
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