login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Product of n-th perfect number and n-th perfect number written backwards.
0

%I #11 Jan 15 2022 22:26:05

%S 36,2296,344224,66795904,2123921902809088,55917383475391234048,

%T 113139095670780538912768,18936964716073275231635792697644548096,

%U 17844842231875188005737387074890396164121166838056340379818586412691750912

%N Product of n-th perfect number and n-th perfect number written backwards.

%H Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.

%F a(n) = A000396(n)*A135624(n).

%e a(2)=2296 because the second perfect number is 28 and 28*82=2296.

%t # IntegerReverse[#]&/@PerfectNumber[Range[10]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Nov 29 2020 *)

%Y Cf. A000396, A133019, A135624.

%K base,nonn

%O 1,1

%A _Omar E. Pol_, Feb 20 2008

%E More terms from _R. J. Mathar_, Jun 24 2009