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Search: id:A096302
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| A096302 |
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Number of combinations of two natural numbers that together have n digits. |
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+0
1
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| 81, 1620, 24300, 324000, 4050000, 48600000, 567000000, 6480000000, 72900000000, 810000000000, 8910000000000, 97200000000000, 1053000000000000, 11340000000000000, 121500000000000000, 1296000000000000000
(list; graph; listen)
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OFFSET
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2,1
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FORMULA
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a(n) = sum[i = 0 to n-1]C(n-1, i)*9^(i+1)*i
a(n) = 81*(n-1)*10^(n-2). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Jun 26 2004
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MATHEMATICA
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f[n_] := Sum[Binomial[n - 1, i]*9^(i + 1)*i, {i, 0, n}]; Table[ a[n], {n, 2, 17}] (from Robert G. Wilson v Jun 30 2004)
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CROSSREFS
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Cf. A053541.
Adjacent sequences: A096299 A096300 A096301 this_sequence A096303 A096304 A096305
Sequence in context: A059977 A116205 A110921 this_sequence A107914 A050634 A065791
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KEYWORD
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nonn
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AUTHOR
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Hagai Helman (Helman(AT)actcom.net.il), Jun 25 2004
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 30 2004
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