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Triangle read by rows: row n consists of (n, n, (n+1), (n+2), (n+3), ...).
3

%I #12 Feb 08 2022 19:48:11

%S 0,1,1,2,2,3,3,3,4,5,4,4,5,6,7,5,5,6,7,8,9,6,6,7,8,9,10,11,7,7,8,9,10,

%T 11,12,13,8,8,9,10,11,12,13,14,15,9,9,10,11,12,13,14,15,16,17,10,10,

%U 11,12,13,14,15,16,17,18,19,11,11,12,13,14,15,16

%N Triangle read by rows: row n consists of (n, n, (n+1), (n+2), (n+3), ...).

%C Row sums = A005449: (0, 2, 7, 15, 26, 40, 57, ...).

%H Harvey P. Dale, <a href="/A134403/b134403.txt">Table of n, a(n) for n = 0..1000</a>

%F Equals (A000012 * A134402 + A134402 * A000012) - A000012.

%e First few rows of the triangle:

%e 0;

%e 1, 1;

%e 2, 2, 3;

%e 3, 3, 4, 5;

%e 4, 4, 5, 6, 7;

%e 5, 5, 6, 7, 8, 9;

%e 6, 6, 7, 8, 9, 10, 11;

%e 7, 7, 8, 9, 10, 11, 12, 13;

%e ...

%t Table[{n,n+Range[0,n-1]},{n,0,20}]//Flatten (* _Harvey P. Dale_, Dec 26 2020 *)

%Y Cf. A134402, A005449.

%K nonn,tabl

%O 0,4

%A _Gary W. Adamson_, Oct 23 2007

%E Leading term changed from 1 to 0 by _N. J. A. Sloane_, Apr 06 2008

%E Corrected and extended by _Harvey P. Dale_, Dec 26 2020