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 A177994 Triangle read by rows, A177990 * A070909 3

%I

%S 1,1,1,2,1,1,2,1,1,1,3,1,2,1,1,3,1,2,1,1,1,4,1,3,1,2,1,1,4,1,3,1,2,1,

%T 1,1,5,1,4,1,3,1,2,1,1,5,1,4,1,3,1,2,1,1,1

%N Triangle read by rows, A177990 * A070909

%C Row sums = A101881: (1, 2, 4, 5, 8, 9, 13, 14,...).

%H Reinhard Zumkeller, <a href="/A177994/b177994.txt">Rows n = 0..100 of triangle, flattened</a>

%F As infinite lower triangular matrices, A177990 * A070909

%e First few rows of the triangle =

%e 1;

%e 1, 1;

%e 2, 1, 1;

%e 2, 1, 1, 1;

%e 3, 1, 2, 1, 1;

%e 3, 1, 2, 1, 1, 1;

%e 4, 1, 3, 1, 2, 1, 1;

%e 4, 1, 3, 1, 2, 1, 1, 1;

%e 5, 1, 4, 1, 3, 1, 2, 1, 1;

%e 5, 1, 4, 1, 3, 1, 2, 1, 1, 1;

%e 6, 1, 5, 1, 4, 1, 3, 1, 2, 1, 1;

%e 6, 1, 5, 1, 4, 1, 3, 1, 2, 1, 1, 1;

%e 7, 1, 6, 1, 5, 1, 4, 1, 3, 1, 2, 1, 1;

%e 7, 1, 6, 1, 5, 1, 4, 1, 3, 1, 2, 1, 1, 1;

%e ...

%o a177994 n k = a177994_tabl !! n !! k

%o a177994_row n = a177994_tabl !! n

%o a177994_tabl = [1] : [1,1] : map f a177994_tabl

%o where f xs@(x:_) = (x + 1) : 1 : xs

%o -- _Reinhard Zumkeller_, Feb 20 2015

%Y Cf. A177991 = A070909 * A177990.

%Y Cf. A101881.

%K nonn,tabl

%O 0,4

%A _Gary W. Adamson_, May 16 2010

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Last modified March 26 10:18 EDT 2019. Contains 321491 sequences. (Running on oeis4.)