|
%I #19 Jan 02 2022 11:23:00
%S 2,6,272,6006,289982,2629262,6039306,27999972,28233282,2704884072,
%T 20278187202,20591819502,2592587852952,2936231326392,21809166190812,
%U 27237788773272,229145919541922,233552101255332,250087292780052,2243922442293422,2570769009670752,20333113431133302,27785925652958772
%N Palindromes of the form n(n+1).
%H P. De Geest, <a href="http://www.worldofnumbers.com/consec.htm">Palindromic pronic numbers of the form n(n+1)</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PalindromicNumber.html">Palindromic Number.</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PronicNumber.html">Pronic Number.</a>
%e 272 belongs to the sequence as 272 = 16*17 is a palindrome.
%t Select[2*Accumulate[Range[15820000]],IntegerDigits[#] == Reverse[ IntegerDigits[#]]&] (* _Harvey P. Dale_, Sep 03 2013 *)
%o (Python)
%o A028337_list, n = [], 0
%o for i in range(2,10**6,2):
%o ....n += i
%o ....s = str(n)
%o ....if s == s[::-1]:
%o ........A028337_list.append(n) # _Chai Wah Wu_, Jan 15 2015
%Y Cf. A028336.
%K nonn,base
%O 1,1
%A _Patrick De Geest_
%E a(20)-a(23) from _G. C. Greubel_, Nov 04 2017
|
