This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A293023 #23 Jan 05 2025 19:51:41 %S A293023 0,1,2,5,12,70 %N A293023 Generalized pentagonal numbers that are also Pell numbers. %C A293023 Intersection of A000129 and A001318. %C A293023 Except for 0 and 2, these are also ordinary pentagonal numbers. %C A293023 All terms are shown, as confirmed by Siva Rama Prasad and Srinivasa Rao (2002). %C A293023 All (generalized) g-gonal numbers in the Pell sequence up to g=20 have been determined, see Tengely (2009). %H A293023 V. Sima Rama Prasad and B. Srinivasa Rao, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/40-3/prasad.pdf">Pentagonal Numbers in the Pell Sequence and Diophantine Equations 2x^2=y^2(3y-1)^2+-2</a>, The Fibonacci Quarterly, Vol. 40, No. 3 (2002), 233-241. %H A293023 Szabolcs Tengely, <a href="http://shrek.unideb.hu/~tengely/G-gonal-FQ.pdf">Finding g-gonal numbers in recurrence sequences</a>, Fibonacci Quarterly, vol.46/47, No. 3 (2009), 235-240. %Y A293023 Cf. A000129, A001318. %Y A293023 Cf. A039595, A248506, A292851. %K A293023 nonn,fini,easy,full %O A293023 0,3 %A A293023 _Tomohiro Yamada_, Sep 29 2017