

A077341


Triangle in which nth row contains the first n numbers, not already present, that begin with n.


5



1, 2, 20, 3, 30, 31, 4, 40, 41, 42, 5, 50, 51, 52, 53, 6, 60, 61, 62, 63, 64, 7, 70, 71, 72, 73, 74, 75, 8, 80, 81, 82, 83, 84, 85, 86, 9, 90, 91, 92, 93, 94, 95, 96, 97, 10, 100, 101, 102, 103, 104, 105, 106, 107, 108, 11, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 12
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OFFSET

1,2


COMMENTS

Every positive number appears exactly once. Proof: N will appear as the first term of row N, unless it has already appeared. And no term is repeated, by definition.
The first term of the 20th row is 200 unlike the 20th row of A077339 where it is 20.


LINKS

M. F. Hasler, Table of n, a(n) for n = 1..5350


EXAMPLE

Triangle begins:
1
2 20
3 30 31
4 40 41 42
5 50 51 52 53
...


PROG

(PARI) {u=[]; for(m=1, 19, o=0; for(n=1, m, while(setsearch(u, a=A077339(m, n+o)), o++); u=setunion(u, Set(a)); print1(a", ")))} \\ M. F. Hasler, Jan 08 2013


CROSSREFS

Cf. A077339, A077340 (see there for differences), A077342, A077343.
Sequence in context: A082259 A342077 A077339 * A344545 A076495 A308387
Adjacent sequences: A077338 A077339 A077340 * A077342 A077343 A077344


KEYWORD

base,easy,nonn,tabl


AUTHOR

Amarnath Murthy, Nov 05 2002


EXTENSIONS

Edited by N. J. A. Sloane, Jun 12 2007


STATUS

approved



