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%I #13 Jan 14 2024 13:32:28
%S 0,1,5,22,210,287,782,1001,2882,7740,15251,77180,565187,720027,781565,
%T 7081807,7451547,26811862,54177145,206489067,246214610,760984602,
%U 1050660501,1085885801,1528888251,2642326276,2911771192,6726232462,24375132126,62123157342
%N Both k and the reverse of k are pentagonal numbers (A000326).
%e 565187=P(614) and 781565=P(722), where P(k) = k*(3*k-1)/2 is the k-th pentagonal number.
%o (PARI) lista(nn) = for (n=0, nn, my(P = n*(3*n-1)/2); if (ispolygonal(fromdigits(Vecrev(digits(P))), 5), print1(P, ", "));); \\ _Michel Marcus_, May 22 2022
%Y Cf. A000326, A061455, A061457.
%K base,nonn
%O 1,3
%A _Giovanni Resta_, Jan 28 2006
%E 0 and additional terms from _Jon E. Schoenfield_, May 22 2022
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