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A214270 Number of compositions of n where the difference between largest and smallest parts equals 1 and adjacent parts are unequal. 3
0, 0, 2, 1, 3, 2, 4, 2, 4, 4, 4, 3, 5, 4, 6, 2, 6, 6, 4, 4, 6, 6, 6, 3, 7, 4, 8, 6, 4, 6, 6, 6, 8, 4, 8, 4, 6, 8, 8, 5, 5, 8, 6, 4, 12, 6, 6, 4, 8, 8, 6, 8, 8, 6, 8, 4, 8, 8, 8, 9, 5, 6, 12, 2, 8, 8, 10, 8, 6, 8, 6, 8, 8, 6, 10, 6, 12, 8, 4, 6, 10, 8, 8, 7, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000

EXAMPLE

a(3) = 2: [2,1], [1,2].

a(4) = 1: [1,2,1].

a(5) = 3: [3,2], [2,3], [2,1,2].

a(14) = 4: [5,4,5], [4,3,4,3], [3,4,3,4], [2,1,2,1,2,1,2,1,2].

a(19) = 4: [9,10], [6,7,6], [10,9], [1,2,1,2,1,2,1,2,1,2,1,2,1].

a(25) = 7: [13,12], [12,13], [8,9,8], [4,3,4,3,4,3,4], [3,2,3,2,3,2,3,2,3,2], [2,3,2,3,2,3,2,3,2,3], [1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1].

MAPLE

a:= proc(n) local m, r, s, t;

       r, s, t:= 0, 1, 2;

       while s+t<=n do m:= irem(n, s+t);

         r:= r+ `if`(m=0, 2, `if`(m in {s, t}, 1, 0));

         s, t:= s+1, t+1

       od; r

    end:

seq(a(n), n=1..100);

CROSSREFS

Column k=1 of A214269.

Sequence in context: A028914 A204539 A302604 * A289440 A290636 A106466

Adjacent sequences:  A214267 A214268 A214269 * A214271 A214272 A214273

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 09 2012

STATUS

approved

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Last modified August 4 09:03 EDT 2020. Contains 336201 sequences. (Running on oeis4.)