A081994 Triangle read by rows in which the n-th row contains n numbers not occurring earlier such that every entry is coprime to all the members of the row and column it belongs.

1, 2, 3, 5, 4, 7, 9, 11, 8, 13, 17, 19, 15, 14, 23, 29, 25, 31, 27, 16, 37, 41, 43, 47, 53, 21, 10, 59, 49, 61, 67, 55, 71, 39, 32, 73, 79, 83, 89, 97, 65, 77, 51, 38, 101, 103, 91, 107, 109, 113, 127, 95, 33, 34, 131, 121, 137, 139, 149, 151, 157, 161, 85, 57, 26, 163, 167

Offset

1,2

Comments

Observation: The second leading diagonal contains even numbers and all other diagonals mandatorily contain odd numbers. (Proof?)

Links

Table of n, a(n) for n=1..67.

Example

Triangle begins:
1
2 3
5 4 7
9 11 8 13
17 19 15 14 23
...

Crossrefs

Cf. A081995, A081996, A081997.

Sequence in context: A358093 A269367 A322863 * A249064 A257489 A090252

Adjacent sequences: A081991 A081992 A081993 * A081995 A081996 A081997

Keyword

tabl,nonn

Author

Amarnath Murthy, Apr 05 2003

Extensions

Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 29 2003

Status

approved