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Search: id:A117823
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| A117823 |
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a(0) = 0, a(1) = 1; for n >= 2, a(n) = a(n-1) + a(n-2) - n if that number is positive and not already in the sequence, otherwise a(n) = a(n-1) + a(n-2) + n. |
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+0
4
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| 0, 1, 3, 7, 6, 8, 20, 21, 33, 45, 68, 102, 158, 247, 391, 623, 998, 1604, 2584, 4169, 6733, 10881, 17592, 28450, 46018, 74443, 120435, 194851, 315258, 510080, 825308, 1335357, 2160633, 3495957, 5656556, 9152478, 14808998, 23961439, 38770399
(list; graph; listen)
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OFFSET
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0,3
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MAPLE
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a[0]:=0: a[1]:=1: A:={0, 1}: for n from 2 to 42 do if a[n-1]+a[n-2]-n>0 and member(a[n-1]+a[n-2]-n, A)=false then a[n]:=a[n-1]+a[n-2]-n: A:=A union {a[n-1]+a[n-2]-n} else a[n]:=a[n-1]+a[n-2]+n: A:=A union {a[n-1]+a[n-2]+n} fi: od: seq(a[n], n=0..42); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 30 2006
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CROSSREFS
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Cf. A079053, A005132, A117821, A117822, A117824.
Sequence in context: A021883 A075785 A105735 this_sequence A070882 A109635 A095360
Adjacent sequences: A117820 A117821 A117822 this_sequence A117824 A117825 A117826
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Apr 30 2006
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 30 2006
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