A079786 Triangle read by rows in which the n-th row begins with n and contains tau(n) numbers. The r-th term from right is the largest number < n with r divisors, for 1<= r <= tau(n).

1, 2, 1, 3, 1, 4, 3, 1, 5, 1, 6, 4, 5, 1, 7, 1, 8, 4, 7, 1, 9, 7, 1, 10, 9, 7, 1, 11, 1, 12, 10, 9, 11, 1, 13, 1, 14, 9, 13, 1, 15, 9, 13, 1, 16, 15, 9, 13, 1, 17, 1, 18, 16, 15, 9, 17, 1, 19, 1, 20, 16, 15, 9, 19, 1, 21, 9, 19, 1, 22, 9, 19, 1, 23, 1, 24, 20, 16, 22, 9, 23, 1, 25, 23, 1, 26, 25

Offset

0,2

Comments

The number of terms in the n-th row = tau(n).

Links

Table of n, a(n) for n=0..86.

Example

1
2 1
3 1
4 3 1
5 1
6 4 5 1
7 1
8 4 7 1
9 7 1
...

Prog

(PARI) print(1, ", "); for(i=2, 50, v=[1]; for(j=2, sigma(i, 0), forstep(k=i, 1, -1, if(sigma(k, 0)==j, v=concat(v, k); break))); forstep(l=length(v), 1, -1, print1(v[l], ", ")); print()) - Lambert Herrgesell (zero815(AT)googlemail.com), Mar 13 2006

Crossrefs

Cf. A079787.

Sequence in context: A354185 A322994 A256147 * A032451 A214494 A088445

Adjacent sequences: A079783 A079784 A079785 * A079787 A079788 A079789

Keyword

nonn,tabf

Author

Amarnath Murthy, Feb 03 2003

Extensions

More terms from Lambert Herrgesell (zero815(AT)googlemail.com), Mar 13 2006

Status

approved