A093849 Row sums of triangle A093846.

9, 153, 2097, 26496, 319995, 3749994, 42999985, 484999992, 5399999991, 59499999990, 649999999935, 7049999999988, 75999999999924, 814999999999941, 8699999999999985, 92499999999999984, 979999999999999902

Offset

1,1

Links

G. C. Greubel, Table of n, a(n) for n = 1..990

Formula

a(n) = n*(2*10^(n-1) - 2 + (n+1)*floor(9*10^(n-1)/n))/2.

Mathematica

Table[n*(2*10^(n-1) -2 +(n+1)*Floor[9*10^(n-1)/n])/2, {n, 1, 20}] (* G. C. Greubel, Mar 22 2019 *)

Prog

(PARI) {a(n) = n*(2*10^(n-1) -2 +(n+1)*floor(9*10^(n-1)/n))/2}; \\ G. C. Greubel, Mar 22 2019
(Magma) [n*(2*10^(n-1) -2 +(n+1)*Floor(9*10^(n-1)/n))/2: n in [1..20]]; // G. C. Greubel, Mar 22 2019
(Sage) [n*(2*10^(n-1) -2 +(n+1)*floor(9*10^(n-1)/n))/2 for n in (1..20)] # G. C. Greubel, Mar 22 2019

Crossrefs

Cf. A093846.

Sequence in context: A143905 A274502 A249642 * A165232 A246641 A169958

Adjacent sequences: A093846 A093847 A093848 * A093850 A093851 A093852

Keyword

base,easy,nonn

Author

Amarnath Murthy, Apr 18 2004

Extensions

Edited and extended by David Wasserman, Mar 26 2007

Status

approved