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Triangle read by rows: A002024 + A128076 - A000012 as infinite lower triangular matrices.
1

%I #8 Jun 07 2023 06:21:50

%S 1,4,3,7,6,5,10,9,8,7,13,12,11,10,9,16,15,14,13,12,11,19,18,17,16,15,

%T 14,13,22,21,20,19,18,17,16,15,25,24,23,22,21,20,19,18,17,28,27,26,25,

%U 24,23,22,21,20,19,31,30,29,28,27,26,25,24,23,22,21,34,33,32,31,30,29,28,27,26,25,24,23

%N Triangle read by rows: A002024 + A128076 - A000012 as infinite lower triangular matrices.

%C Row sums = A000566, the heptagonal numbers: (1, 7, 18, 34, 55, ...).

%F By rows, (n+1) terms of 3n+1, 3n, 3n-1, ...

%e First few rows of the triangle:

%e 1;

%e 4, 3;

%e 7, 6, 5;

%e 10, 9, 8, 7;

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

%e 16, 15, 14, 13, 12, 11;

%e 19, 18, 17, 16, 15, 14, 13;

%e ...

%Y Cf. A000566, A002024, A128076.

%K nonn,tabl

%O 0,2

%A _Gary W. Adamson_, Jul 08 2007

%E a(5) = 5, a(30) = 20 corrected and more terms from _Georg Fischer_, Jun 07 2023