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Search: id:A125421
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| A125421 |
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Number of base 9 circular n-digit numbers with adjacent digits differing by 7 or less. |
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+0
1
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| 1, 9, 79, 681, 5987, 52649, 463087, 4073225, 35827395, 315131721, 2771845519, 24380686185, 214448408099, 1886252068073, 16591155401263, 145933007686601, 1283602149301635, 11290348248219273, 99308001030865615
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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[Empirical] a(base,n)=a(base-1,n)+F(7) for base>=7.int(n/2)+1, and F(d) is the largest coefficient in (1+x+...+x^(2d))^n
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PROGRAM
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(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>7)+($[(i+1)mod N]`-$[i]`>7))
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CROSSREFS
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Adjacent sequences: A125418 A125419 A125420 this_sequence A125422 A125423 A125424
Sequence in context: A044577 A126632 A125909 this_sequence A083411 A081108 A018913
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhh(AT)cadence.com), Dec 28 2006
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