A122415 Triangle T(n,k) for 1 < k < n read by rows, where T(n,k) = 1 if gcd(n,k) is prime, 0 otherwise.

0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0

Offset: 3

Author

Klaus Brockhaus, Sep 03 2006

Keywords

• nonn
• tabl

Comments

Triangle defined in A122414 without first column and main diagonal.

Crossrefs

Cf. A122414.

Row sums are in A087625. [From Klaus Brockhaus, May 29 2009]

Programs

PARI

{m=14; v=vector(m,x,vector(x)); for(n=1,m,for(k=1,n-1,if(isprime(gcd(n+2,k+1)),v[n][k]=1))); for(n=1,m,for(k=1,n,print1(v[n][k],",")))}