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Search: id:A126643
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| A126643 |
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a(n) is the number of integers k less than 10^n such that the decimal representation of k lacks the digits 1,2,3,4, at least one of digits 5,6 and at least one of digits 7,8,9. |
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+0
2
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| 6, 34, 180, 886, 4116, 18334, 79260, 335446, 1398276, 5765134, 23581740, 95900806, 388345236, 1567647934, 6313474620, 25382710966, 101917608996, 408831386734, 1638809709900, 6565693949926, 26294146373556, 105270707701534
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
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FORMULA
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a(n)=6*4^n-9*3^n+5*2^n-1
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EXAMPLE
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a(8)=335446
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MAPLE
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f:=n->6*4^n-9*3^n+5*2^n-1;
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CROSSREFS
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Cf. A125630, A125948, A125947, A125946, A125945, A125940, A125909, A125908, A125880, A125897, A125904, A125858.
Sequence in context: A086934 A009469 A144142 this_sequence A084775 A085351 A125343
Adjacent sequences: A126640 A126641 A126642 this_sequence A126644 A126645 A126646
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KEYWORD
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nonn
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AUTHOR
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Aleksandar M. Janjic and Milan R. Janjic (agnus(AT)blic.net), Feb 08 2007
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