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A077341 Triangle in which n-th 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 (list; table; graph; refs; listen; history; text; internal format)
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

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Last modified September 20 13:56 EDT 2021. Contains 347586 sequences. (Running on oeis4.)