A133820 - OEIS

%I #11 Mar 05 2014 15:30:51

%S 1,1,8,1,8,27,1,8,27,64,1,8,27,64,125,1,8,27,64,125,216,1,8,27,64,125,

%T 216,343,1,8,27,64,125,216,343,512,1,8,27,64,125,216,343,512,729,1,8,

%U 27,64,125,216,343,512,729,1000

%N Triangle whose rows are sequences of increasing cubes: 1; 1,8; 1,8,27; ... .

%C Reading the triangle by rows produces the sequence 1,1,8,1,8,27,1,8,27,64,..., analogous to A002260.

%H Reinhard Zumkeller, <a href="/A133820/b133820.txt">Rows n = 1..120 of triangle, flattened</a>

%F O.g.f.: (1+4qx+q^2x^2)/((1-x)(1-qx)^4) = 1 + x(1 + 8q) + x^2(1 + 8q + 27q^2) + ... .

%e Triangle starts

%e 1;

%e 1, 8;

%e 1, 8, 27;

%e 1, 8, 27, 64;

%e 1, 8, 27, 64, 125;

%t Module[{nn=10,c},c=Range[nn]^3;Flatten[Table[Take[c,n],{n,10}]]] (* _Harvey P. Dale_, Mar 05 2014 *)

%o (Haskell)

%o a133820 n k = a133820_tabl !! (n-1) !! (k-1)

%o a133820_row n = a133820_tabl !! (n-1)

%o a133820_tabl = map (`take` (tail a000578_list)) [1..]

%o -- _Reinhard Zumkeller_, Nov 11 2012

%Y Cf. A000537 (row sums), A002260, A019522, A133819, A133821, A133823.

%K easy,nonn,tabl

%O 1,3

%A _Peter Bala_, Sep 25 2007

%E Offset changed by _Reinhard Zumkeller_, Nov 11 2012