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A141396 Triangle read by rows, antidiagonals of a multiplication table: 3^n * (numbers not multiples of 3). 3

%I

%S 1,2,3,4,6,9,5,12,18,27,7,15,36,54,81,8,21,45,108,162,243,10,24,63,

%T 135,324,486,729,11,30,72,189,405,972,1458,2187,13,33,90,216,567,1215,

%U 2916,4374,6561,14,39,99,270,648,1701,3645,8748,13122,19683,16,42,117,297

%N Triangle read by rows, antidiagonals of a multiplication table: 3^n * (numbers not multiples of 3).

%C Ternary representation of terms in n-th row have n rightmost adjacent zeros.

%C Row sums = A141397: (1, 5, 19 62, 193, 587, ...).

%H Ivan Neretin, <a href="/A141396/b141396.txt">Table of n, a(n) for n = 0..5049</a>

%F Triangle read by rows, descending antidiagonals of the multiplication table: (top row, numbers not multiples of 3); leftmost column, 3^n.

%e The array begins:

%e 1, 2, 4, 5, 7, ...

%e 3, 6, 12, 15, 21, ...

%e 9, 18, 36, 45, 63, ...

%e 27, 54, 108, 135, 189, ...

%e 81, 162, 324, 405, 567, ...

%e ...

%e Descending antidiagonals of the array give

%e 1;

%e 2, 3;

%e 4, 6, 9;

%e 5, 12, 18, 27;

%e 7, 15, 36, 54, 81;

%e 8, 21, 45, 108, 162, 243;

%e 10, 24, 63, 135, 324, 486, 729;

%e 11, 30, 72, 189, 405, 972, 1458, 2187;

%e ...

%t Flatten[Table[3^k*Quotient[(3 (m - k) - 1), 2], {m, 0, 10}, {k, 0, m - 1}]] (* _Ivan Neretin_, Nov 26 2016 *)

%Y Cf. A001651, A141397.

%K nonn,tabl

%O 0,2

%A _Gary W. Adamson_, Jun 29 2008

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Last modified November 22 16:26 EST 2019. Contains 329396 sequences. (Running on oeis4.)