A120853 Triangle read by rows, where t(n,1) = 1, t(n,m) = t(n,m-1) + (largest nonprime {1 or composite} in row {n-1}).

1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 5, 9, 13, 17, 1, 10, 19, 28, 37, 46, 1, 47, 93, 139, 185, 231, 277, 1, 232, 463, 694, 925, 1156, 1387, 1618, 1, 1619, 3237, 4855, 6473, 8091, 9709, 11327, 12945, 1, 12946, 25891, 38836, 51781, 64726, 77671, 90616, 103561, 116506

Offset

1,3

Links

Table of n, a(n) for n=1..55.

Example

9 is the largest composite in row 5 of the triangle. So t(6,m) = 1 + 9*(m-1), for 1 <= m <= 6.
Triangle begins:
  1,
  1, 2,
  1, 2, 3,
  1, 2, 3,  4,
  1, 5, 9, 13, 17,
  ...

Prog

(PARI) {z=10; w=[]; for(n=1, z, k=0; for(j=1, #w, if(k<w[j]&&(w[j]==1||!isprime(w[j])), k=w[j])); print1(a=1, ", "); w=[a]; for(m=2, n, a=k+a; print1(a, ", "); w=concat(w, a)))} \\ _Klaus Brockhaus, Aug 17 2006_

Crossrefs

Cf. A120852.

Row sums are in A160965. [Klaus Brockhaus, May 31 2009]

Sequence in context: A194973 A195113 A120418 * A175022 A243613 A194844

Adjacent sequences: A120850 A120851 A120852 * A120854 A120855 A120856

Keyword

nonn,tabl

Author

Leroy Quet, Jul 08 2006

Extensions

More terms from Klaus Brockhaus, Aug 17 2006

Status

approved