cp's OEIS Frontend

A247364 Riordan array (f(x), (f(x)-1)/f(x)) where f(x) = (1 + x - sqrt(1 - 2x - 3x^2))/(2*x).

%I A247364 #12 Jul 24 2017 16:44:48
%S A247364 1,1,1,1,1,1,2,2,1,1,4,4,3,1,1,9,9,6,4,1,1,21,21,15,8,5,1,1,51,51,36,
%T A247364 22,10,6,1,1,127,127,91,54,30,12,7,1,1,323,323,232,142,75,39,14,8,1,1,
%U A247364 835,835,603,370,205,99,49,16,9,1,1,2188,2188,1585,983
%N A247364 Riordan array (f(x), (f(x)-1)/f(x)) where f(x) = (1 + x - sqrt(1 - 2x - 3x^2))/(2*x).
%C A247364 This is essentially the reversal of the triangle in A034928, and A204849 with a duplicated first column.
%C A247364 Row sums are A005554(n+1).
%H A247364 Reinhard Zumkeller, <a href="/A247364/b247364.txt">Rows n = 0..125 of triangle, flattened</a>
%F A247364 T(n,0) = A086246(n+1), T(n+1,1) = A001006(n), T(n+2,2) = A005043(n+2).
%e A247364 Triangle begins:
%e A247364 1
%e A247364 1, 1
%e A247364 1, 1, 1
%e A247364 2, 2, 1, 1
%e A247364 4, 4, 3, 1, 1
%e A247364 9, 9, 6, 4, 1, 1
%e A247364 21, 21, 15, 8, 5, 1, 1
%e A247364 51, 51, 36, 22, 10, 6, 1, 1
%e A247364 Production matrix begins:
%e A247364 1, 1
%e A247364 0, 0, 1
%e A247364 1, 1, 0, 1
%e A247364 1, 1, 1, 0, 1
%e A247364 1, 1, 1, 1, 0, 1
%e A247364 1, 1, 1, 1, 1, 0, 1
%e A247364 1, 1, 1, 1, 1, 1, 0, 1
%o A247364 (Haskell)
%o A247364 a247364 n k = a247364_tabl !! n !! k
%o A247364 a247364_row n = a247364_tabl !! n
%o A247364 a247364_tabl = [1] : (map reverse a034928_tabf)
%o A247364 -- _Reinhard Zumkeller_, Sep 20 2014
%Y A247364 Cf. A001006, A005043, A005554, A034928, A086246.
%K A247364 nonn,tabl
%O A247364 0,7
%A A247364 _Philippe Deléham_, Sep 14 2014