A061205 a(n) = n times R(n) where R(n) (A004086) is the digit reversal of n.

0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 10, 121, 252, 403, 574, 765, 976, 1207, 1458, 1729, 40, 252, 484, 736, 1008, 1300, 1612, 1944, 2296, 2668, 90, 403, 736, 1089, 1462, 1855, 2268, 2701, 3154, 3627, 160, 574, 1008, 1462, 1936, 2430, 2944, 3478, 4032, 4606

Offset: 0

Author

Amarnath Murthy, Apr 21 2001

Keywords

• nonn
• base
• look

Comments

Every third term is divisible by 9, no other term is divisible by 3. - Alonso del Arte, Mar 04 2013

Examples

			a(10) = 10 = 10 * 01.
a(11) = 121 = 11 * 11.
a(12) = 252 = 12 * 21.
a(13) = 403 = 13 * 31.
		

Links

• Harry J. Smith and Indranil Ghosh, Table of n, a(n) for n = 0..10000 (first 1001 terms from Harry J. Smith)

Crossrefs

Cf. A004086, A203924 (triple repetitions).

Programs

Haskell

a061205 n = a004086 n * n
-- Reinhard Zumkeller, Apr 10 2012, Apr 29 2011

Mathematica

#*FromDigits[Reverse[IntegerDigits[#]]] &/@Range[0, 49]  (* Ant King, Jan 07 2012 *)
#*IntegerReverse[#]& /@ Range[0, 49] (* Jean-François Alcover, Oct 27 2019 *)

PARI

rev(k) = subst(Polrev(digits(k)), x, 10);
a(n) = n*rev(n); \\ Michel Marcus, Feb 14 2015

PARI

a(n) = n*fromdigits(Vecrev(digits(n))); \\ Michel Marcus, May 28 2018

Python

def A061205(n):
    return n*A004086(n) # Indranil Ghosh, Jan 09 2017

Extensions

Corrected and extended by Patrick De Geest, Jun 04 2001