A135326 Sum of all n-digit terms of A005043.

12, 142, 835, 5798, 124932, 853467, 6536382, 50852019, 1234849644, 9043402501, 73007772802, 593742784829, 4859761676391, 125320157443726, 953467954114363, 7939655757745265, 66368199913921497, 556704809728838604, 4684478925507420069, 125076091920076709793

Offset

1,1

Links

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

Example

Sum of all 1-digit Riordan numbers is 1 + 0 + 1 + 1 + 3 + 6 = 12.
Sum of all 2-digit Riordan numbers is 15 + 36 + 91 = 142.
Sum of all 3-digit Riordan numbers is 232 + 603 = 835.

Mathematica

digNum[n_] := Length @ IntegerDigits[n]; rio[0] = 1; rio[1] = 0; rio[n_] := rio[n] = (n - 1)*(2*rio[n - 1] + 3*rio[n - 2])/(n + 1); digCount = 0; sum = 0; cumsum = {}; Do[r = rio[n]; If[digNum[r] > digCount, digCount++; AppendTo[cumsum, sum]]; sum += r, {n, 0, 50}]; Differences[cumsum] (* Amiram Eldar, Nov 30 2019 *)

Crossrefs

Cf. A005043.

Sequence in context: A124206 A061636 A266177 * A056340 A056330 A158516

Adjacent sequences: A135323 A135324 A135325 * A135327 A135328 A135329

Keyword

nonn,base,less

Author

Parthasarathy Nambi, Dec 06 2007

Extensions

More terms from Amiram Eldar, Nov 30 2019

Status

approved