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Search: id:A137403
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| A137403 |
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A multiswitched integer differential-type sequence designed to be mostly odd: two types of integer differential sequences are switched in a way that is made odd: 1) a(n)=2*a(n-1)-a(n-2); 2) a(n)=3*a(n-1)-3*a(n-2)+a(n-3); the one back versions are 3) a(n)=2*a(n-2)-a(n-3); 4) a(n)=3*a(n-2)-3*a(n-3)+a(n-4). |
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1
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| 2, 3, 5, 4, 3, 3, 3, 4, 3, 5, 2, 7, 12, 17, 17, 22, 27, 27, 27, 22, 27, 17, 32, 7, -18, -43, -43, -68, -93, -93, -93, -68, -93, -43, -118, 7, 132, 257, 257, 382, 507, 507, 507, 382, 507, 257, 632, 7, -618, -1243
(list; table; graph; listen)
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OFFSET
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1,1
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COMMENT
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The object is to choose the options so that the most likely outcome is odd; 33 out of the first 50 terms are odd.
Apply[Plus, Table[If[Mod[a0[[n]], 2] == 1, 1, 0], {n, 1, Length[a0]}]].
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MATHEMATICA
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Clear[a] a[1] = 2; a[2] = 3; a[3] = 5; a[n_] := a[n] = If[Mod[3*a[n - 1] - 3*a[n - 2] + a[n - 3], 2] == 0, If[Mod[2*a[n - 1] - a[n - 2], 3] == 0, 2*a[n - 1] - a[n - 2], 2*a[n - 2] - a[n - 3]], If[Mod[3*a[n - 1] - 3*a[n - 2] + a[n - 3], 3] == 0, 3*a[n - 2] - 3*a[n - 3] + a[n - 4], 3*a[n - 1] - 3*a[n - 2] + a[n - 3]]] a0=Table[a[n], {n, 1, 50}]
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CROSSREFS
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Adjacent sequences: A137400 A137401 A137402 this_sequence A137404 A137405 A137406
Sequence in context: A060444 A021981 A068508 this_sequence A082233 A058981 A117339
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KEYWORD
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tabl,sign
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Apr 14 2008, Apr 15 2008
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