A083824 a(n) = digit reversal of 9*n, divided by 9.

0, 1, 9, 8, 7, 6, 5, 4, 3, 2, 1, 11, 89, 79, 69, 59, 49, 39, 29, 19, 9, 109, 99, 78, 68, 58, 48, 38, 28, 18, 8, 108, 98, 88, 67, 57, 47, 37, 27, 17, 7, 107, 97, 87, 77, 56, 46, 36, 26, 16, 6, 106, 96, 86, 76, 66, 45, 35, 25, 15, 5, 105, 95, 85, 75, 65, 55, 34, 24, 14, 4, 104, 94, 84

Offset: 0

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 08 2003

Keywords

• base
• easy
• nonn

Comments

If n is a multiple of 10, then a(n) = a(n/10); if n is not a multiple of 10, then a(a(n)) = n.

Examples

			a(2) = reverse(9*2)/9 = reverse(18)/9 = 81/9 = 9.
		

Crossrefs

Cf. A083822 (analog for 3), A083823, A083825.

Programs

PARI

{for(n=0,73,k=9*n; rev=0; while(k>0,d=divrem(k,10); k=d[1]; rev=10*rev+d[2]); print1(rev/9,","))}

PARI

apply( {A083824(n)=fromdigits(Vecrev(digits(9*n)))/9}, [0..99]) \\ M. F. Hasler, May 21 2021

Extensions

Edited, corrected and extended by Klaus Brockhaus, May 11 2003

Minor edits and extension to offset 0 by M. F. Hasler, May 21 2021