OFFSET
1,5
COMMENTS
Row sums = A023896, (reduced residue system mod n): (1, 1, 3, 4, 10, 6, 21, ...). - Gary W. Adamson, Aug 27 2008
FORMULA
T(n,k) = k if a relative prime of n; 0 otherwise. Replace the "1's" of A054521 with their corresponding column numbers; leaving the zeros.
EXAMPLE
Row 4 = (1, 0, 3, 0) since 1 and 3 are relative primes of 4.
First few rows of the triangle are:
1;
1, 0;
1, 2, 0;
1, 0, 3, 0;
1, 2, 3, 4, 0;
1, 0, 0, 0, 5, 0;
1, 2, 3, 4, 5, 6, 0;
...
PROG
(PARI)
T127368(n, k)={gcd(n, k)==1 & return(k)}
A127368(n)=T127368( t=(sqrt(8*n)+1)\2, n-binomial(t, 2)) \\ M. F. Hasler, Mar 02 2012
CROSSREFS
KEYWORD
AUTHOR
Gary W. Adamson, Jan 11 2007
EXTENSIONS
Corrected at the suggestion of Kevin Ryde by Alois P. Heinz, Mar 02 2012
STATUS
approved