A073729 Concatenation of initial and final digits of n in decimal representation.

11, 22, 33, 44, 55, 66, 77, 88, 99, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69

Offset: 1

Author

Reinhard Zumkeller, Aug 05 2002

Keywords

• nonn
• base
• easy
• look

Comments

10 <= a(n) <= 99; a(a(n))=a(n).

Examples

			a(12321)=11; a(3210123)=33; a(59387)=57; a(8923)=83.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A073731, A073730.

Programs

Haskell

a073729 n = 10 * a000030 n + a010879 n  -- Reinhard Zumkeller, Dec 31 2012

Mathematica

Table[FromDigits[{First[x = IntegerDigits[n]], Last[x]}], {n, 69}] (* Jayanta Basu, Jul 08 2013 *)

PARI

a(n)=10*digits(n)[1]+n%10 \\ Charles R Greathouse IV, Dec 28 2012

Formula

a(n) = A000030(n)*10 + A010879(n).