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

0,3

Comments

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

Links

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

Example

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

Mathematica

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

Prog

(PARI) { for (n=0, 1000, x=n; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); write("b061205.txt", n, " ", n*r) ) } \\ Harry J. Smith, Jul 18 2009
(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
(Haskell)
a061205 n = a004086 n * n
-- Reinhard Zumkeller, Apr 10 2012, Apr 29 2011
(Python)
def A061205(n):
    return n*A004086(n) # Indranil Ghosh, Jan 09 2017

Crossrefs

Cf. A004086, A203924 (triple repetitions).

Sequence in context: A361203 A057147 A213630 * A290934 A048387 A035121

Adjacent sequences: A061202 A061203 A061204 * A061206 A061207 A061208

Keyword

nonn,base,look

Author

Amarnath Murthy, Apr 21 2001

Extensions

Corrected and extended by Patrick De Geest, Jun 04 2001

Status

approved