A180175 Diagonal sums of A164844.

1, 10, 101, 1011, 10112, 101123, 1011235, 10112358, 101123593, 1011235951, 10112359544, 101123595495, 1011235955039, 10112359550534, 101123595505573, 1011235955056107, 10112359550561680, 101123595505617787, 1011235955056179467, 10112359550561797254

Offset

1,2

Comments

Sums are built along inclined lines through the triangle with (1,2)-steps in the (row,column) indices. - R. J. Mathar, Aug 19 2010

Links

Table of n, a(n) for n=1..20.

Index entries for linear recurrences with constant coefficients, signature (11,-9,-10).

Formula

From R. J. Mathar, Aug 19 2010: (Start)

G.f.: ( 1-x ) / ( (10*x-1)*(x^2+x-1) ).

a(n) = +11*a(n-1) -9*a(n-2) -10*a(n-3).

a(n) = (90*10^n -A022100(n))/89. (End)

Example

From R. J. Mathar, Aug 19 2010: (Start)
One example is a(5), the sum of numbers in parentheses:
  1;
  1, 10;
  (1), 11, 100;
  1, 12, (111) ; 1000;;
  1, 13, 123 ; 1111, (10000); (End)

Crossrefs

Cf. A022100, A164844.

Sequence in context: A283508 A261200 A175541 * A267526 A261199 A041041

Adjacent sequences: A180172 A180173 A180174 * A180176 A180177 A180178

Keyword

nonn,easy

Author

Mark Dols, Aug 15 2010

Extensions

More terms from R. J. Mathar, Aug 19 2010

Status

approved