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Search: id:A126521
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| A126521 |
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Number of base 26 n-digit numbers with adjacent digits differing by four or less. |
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+0
2
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| 1, 26, 214, 1806, 15374, 131538, 1128990, 9710910, 83652388, 721363974, 6225222156, 53750847042, 464278918952, 4011329573242, 34664086928592, 299591386800116, 2589524785835700, 22384118655449566, 193499832018326518
(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)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4
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PROGRAM
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(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))
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CROSSREFS
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Cf. Base 26 differing by three or less A126494, two or less A126413, one or less A126380.
Sequence in context: A100242 A042310 A125363 this_sequence A159519 A110486 A098994
Adjacent sequences: A126518 A126519 A126520 this_sequence A126522 A126523 A126524
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net), Dec 28 2006
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