login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A061205 a(n) = n times R(n) where R(n) (A004086) is the digit reversal of n. 15

%I

%S 0,1,4,9,16,25,36,49,64,81,10,121,252,403,574,765,976,1207,1458,1729,

%T 40,252,484,736,1008,1300,1612,1944,2296,2668,90,403,736,1089,1462,

%U 1855,2268,2701,3154,3627,160,574,1008,1462,1936,2430,2944,3478,4032,4606

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

%C Every third term is divisible by 9, no other term is divisible by 3. - _Alonso del Arte_, Mar 04 2013

%H Harry J. Smith and Indranil Ghosh, <a href="/A061205/b061205.txt">Table of n, a(n) for n = 0..10000</a> (first 1001 terms from Harry J. Smith)

%e a(10) = 10 = 10 * 01.

%e a(11) = 121 = 11 * 11.

%e a(12) = 252 = 12 * 21.

%e a(13) = 403 = 13 * 31.

%t #*FromDigits[Reverse[IntegerDigits[#]]] &/@Range[0, 49] (* _Ant King_, Jan 07 2012 *)

%t #*IntegerReverse[#]& /@ Range[0, 49] (* _Jean-Fran├žois Alcover_, Oct 27 2019 *)

%o (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

%o (PARI) rev(k) = subst(Polrev(digits(k)), x, 10);

%o a(n) = n*rev(n); \\ _Michel Marcus_, Feb 14 2015

%o (PARI) a(n) = n*fromdigits(Vecrev(digits(n))); \\ _Michel Marcus_, May 28 2018

%o (Haskell)

%o a061205 n = a004086 n * n

%o -- _Reinhard Zumkeller_, Apr 10 2012, Apr 29 2011

%o (Python)

%o def A061205(n):

%o return n*A004086(n) # _Indranil Ghosh_, Jan 09 2017

%Y Cf. A004086, A203924 (triple repetitions).

%K nonn,base,look

%O 0,3

%A _Amarnath Murthy_, Apr 21 2001

%E Corrected and extended by _Patrick De Geest_, Jun 04 2001

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 13 17:30 EDT 2021. Contains 342936 sequences. (Running on oeis4.)