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Search: id:A130665
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| A130665 |
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a(1) = 1; a(n) = max { 3*a(k)+a(n-k) | 1 <= k <= n/2 }, for n>1. |
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+0
4
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| 1, 4, 7, 16, 19, 28, 37, 64, 67, 76, 85, 112, 121, 148, 175, 256, 259, 268, 277, 304, 313, 340, 367, 448, 457, 484, 511, 592, 619, 700, 781, 1024, 1027, 1036, 1045, 1072, 1081, 1108, 1135, 1216, 1225, 1252, 1279, 1360, 1387, 1468, 1549, 1792, 1801, 1828, 1855
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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D. E. Knuth, Problem submitted to Amer. Math. Monthly, Jun 18 2007.
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FORMULA
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a(2n)=4a(n) and a(2n+1)=3a(n)+a(n+1).
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MAPLE
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u:=3; a[1]:=1; M:=30; for n from 1 to M do a[2*n] := (u+1)*a[n]; a[2*n+1] := u*a[n] + a[n+1]; od; t1:=[seq( a[n], n=1..2*M )];
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CROSSREFS
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Cf. A006046, A130666, A130667.
Adjacent sequences: A130662 A130663 A130664 this_sequence A130666 A130667 A130668
Sequence in context: A037373 A018887 A059014 this_sequence A101534 A110933 A067398
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KEYWORD
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nonn
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AUTHOR
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njas, based on a message from D. E. Knuth, Jun 23 2007
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