A178471 Triangle where T(n,k) is the number of compositions of n where no pair of consecutive part sizes is relative prime, starting with a part of size k.

1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 2, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 4, 0, 2, 0, 1, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 1, 0, 8, 0, 4, 1, 2, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 16, 4, 8, 0, 5, 0, 2, 1, 1, 0, 1, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 33, 1, 16, 0, 8, 1, 4, 0, 2, 0, 1, 0

Offset

1,17

Links

Table of n, a(n) for n=1..104.

Example

The array starts:
1
0 1
0 0 1
0 1 0 1
0 0 0 0 1
0 2 1 1 0 1

Prog

(PARI) am(n)=local(r); r=matrix(n, n, i, j, i==j); for(i=2, n, for(j=1, i-1, for(k=1, j, if(gcd(i-j, k)>1, r[i, i-j]+=r[j, k])))); r

Crossrefs

Cf. A178470 (row sums).

Sequence in context: A293015 A293119 A293133 * A160381 A089311 A086784

Adjacent sequences: A178468 A178469 A178470 * A178472 A178473 A178474

Keyword

nonn,tabl

Author

Franklin T. Adams-Watters, May 28 2010

Status

approved