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A137403 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). 0
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; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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]}]].

LINKS

Table of n, a(n) for n=1..50.

MATHEMATICA

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}]

CROSSREFS

Sequence in context: A284278 A330080 A068508 * A082233 A330806 A058981

Adjacent sequences:  A137400 A137401 A137402 * A137404 A137405 A137406

KEYWORD

tabl,sign

AUTHOR

Roger L. Bagula, Apr 14 2008, Apr 15 2008

STATUS

approved

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Last modified June 18 04:41 EDT 2021. Contains 345098 sequences. (Running on oeis4.)