A083292 a(n) = n*floor(n/10) + (n mod 10).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 40, 43, 46, 49, 52, 55, 58, 61, 64, 67, 90, 94, 98, 102, 106, 110, 114, 118, 122, 126, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 250, 256, 262, 268, 274, 280, 286, 292, 298, 304, 360, 367, 374

Offset: 0

Author

Reinhard Zumkeller, Apr 23 2003

Keywords

• nonn
• easy

Comments

a(n) = T(n,n), as defined in A083291.

Examples

			a(25) = 25*2 + 5 = 55.
		

Links

• N. J. A. Sloane, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 2, -2, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1).

Crossrefs

Cf. A083291. Differs from A122618 starting at n = 100.

Programs

Mathematica

Table[n Floor[n/10]+Mod[n,10],{n,0,70}] (* or *) LinearRecurrence[ {1,0,0,0,0,0,0,0,0,2,-2,0,0,0,0,0,0,0,0,-1,1},{0,1,2,3,4,5,6,7,8,9,10,12,14,16,18,20,22,24,26,28,40},70] (* Harvey P. Dale, May 23 2015 *)

Formula

a(n)= +a(n-1) +2*a(n-10) -2*a(n-11) -a(n-20) +a(n-21). - R. J. Mathar, Feb 20 2011