%I #23 Apr 25 2021 12:14:41
%S 15151,181,141,919,22,121,55,11,111,121,131,141,151,161,171,55,191,
%T 121,22,189949981,484,505,151,11311,757,16661,88,181,72727,33,1111111,
%U 10201,10501,757,2636362,17671,51715,121,616,36163,44,1856581,676,12256565221
%N Smallest multidigit palindromic centered n-gonal number.
%C Is it true that there is no term for n = 56? - _T. D. Noe_, Oct 03 2011
%C No, the smallest multidigit palindromic centered 56-gonal number is 14075098988989057041 with base 709000780. - _Patrick De Geest_, Apr 25 2021
%H Patrick De Geest, <a href="http://www.worldofnumbers.com/centered.htm">Palindromic Centered Polygonal Numbers</a>
%H T. Trotter, <a href="http://trottermath.net/polygonal-numbers/">Polygonal numbers</a>
%e 15151 is the smallest palindromic centered triangular number.
%e 121 is the smallest palindromic centered 40-gonal number.
%t palin[n_] := Module[{d = IntegerDigits[n]}, d == Reverse[d]]; Table[n = 1; While[num = n*k*(n-1)/2 + 1; num < 10 || ! palin[num], n++]; num, {k, 3, 50}] (* _T. D. Noe_, Oct 03 2011 *)
%K nonn,base
%O 3,1
%A _Kausthub Gudipati_, Oct 03 2011
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