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

1,1

Comments

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

Links

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

Formula

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

Example

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

Mathematica

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

Prog

(PARI) a(n)=10*digits(n)[1]+n%10 \\ Charles R Greathouse IV, Dec 28 2012
(Haskell)
a073729 n = 10 * a000030 n + a010879 n  -- Reinhard Zumkeller, Dec 31 2012

Crossrefs

Cf. A073731, A073730.

Sequence in context: A065998 A364275 A351877 * A073730 A367610 A087346

Adjacent sequences: A073726 A073727 A073728 * A073730 A073731 A073732

Keyword

nonn,base,easy,look

Author

Reinhard Zumkeller, Aug 05 2002

Status

approved