# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a121875
Showing 1-1 of 1

%I A121875 #7 Oct 12 2012 14:55:29
%S A121875 1,2,3,3,7,13,5,17,43,89,8,41,142,377,836,13,99,469,1597,4341,10063,
%T A121875 21,239,1549,6765,22541,62011,148149,34,577,5116,28657,117046,382129,
%U A121875 1057792,2581921,55,1393,16897,121393,607771,2354785,7552693,20973217
%N A121875 Triangular array read by rows: see Comments for definition.
%C A121875 Form the square array in which row m satisfies r(0) = r(1) = 1; r(n) = m*r(n-1) + r(n-2):
%C A121875 1 1 2 3 5 8 13 21 ...
%C A121875 1 1 3 7 17 41 99 ...
%C A121875 1 1 4 13 43 142 ...
%C A121875 1 1 5 21 89 377 ...
%C A121875 ...
%C A121875 Now form a triangle by taking the first k terms of column k:
%C A121875 1
%C A121875 2, 3
%C A121875 3, 7, 13
%C A121875 5, 17, 43, 89
%C A121875 8, 41, 142, 377, 836
%C A121875 ...
%t A121875 f[n_Integer] = Module[{a}, a[n] /. RSolve[{a[n] == m*a[n - 1] + a[n - 2], a[0] == 1, a[1] == 1}, a[n], n][[1]] // FullSimplify] a = Table[Table[Rationalize[N[f[n], 100], 0], {m, 1, n}], {n, 1, 10}] Flatten[a]
%Y A121875 Cf. A135597.
%K A121875 nonn,tabl
%O A121875 1,2
%A A121875 _Roger L. Bagula_ and _Gary W. Adamson_, Sep 09 2006
%E A121875 Edited by _N. J. A. Sloane_, Mar 02 2008

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE