A093849 - OEIS

A093849

Row sums of triangle A093846.

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

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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