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Triangle read by rows in which row n lists n terms, starting with 1, with gaps = n-2 between successive terms.
11

%I #15 Jul 25 2023 13:11:42

%S 1,1,1,1,2,3,1,3,5,7,1,4,7,10,13,1,5,9,13,17,21,1,6,11,16,21,26,31,1,

%T 7,13,19,25,31,37,43,1,8,15,22,29,36,43,50,57,1,9,17,25,33,41,49,57,

%U 65,73,1,10,19,28,37,46,55,64,73,82,91,1,11,21,31,41,51,61,71,81

%N Triangle read by rows in which row n lists n terms, starting with 1, with gaps = n-2 between successive terms.

%C Equals A081493 when first column is removed. - _Georg Fischer_, Jul 25 2023

%F T(n,n) = A002061(n-1).

%F T(n,k) = A076110(n-1,k) = 1+(n-2)*(k-1). - _R. J. Mathar_, Mar 30 2023

%e Triangle begins:

%e 1;

%e 1, 1;

%e 1, 2, 3;

%e 1, 3, 5, 7;

%e 1, 4, 7, 10, 13;

%e 1, 5, 9, 13, 17, 21;

%e 1, 6, 11, 16, 21, 26, 31;

%t Table[NestList[#+(n-2)&,1,n-1],{n,20}]//Flatten (* _Harvey P. Dale_, Oct 23 2017 *)

%Y Cf. A002061, A159797, A159798, A162610, A161611, A162612, A162613.

%Y Cf. A060354 (row sums), A081493 (without first column).

%K easy,nonn,tabl

%O 1,5

%A _Omar E. Pol_, Jul 09 2009