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 A292850 #12 Jan 05 2025 19:51:41 %S A292850 1,4,7,18 %N A292850 Lucas numbers that are also generalized heptagonal numbers. %C A292850 Intersection of A000032 and A085787. %C A292850 Except 4, these are also ordinary heptagonal numbers. %C A292850 All terms are shown, as confirmed by Srinivasa Rao (2002). %C A292850 All (generalized) g-gonal numbers in Lucas sequences up to g=20 have been determined, see Tengely (2009). %H A292850 B. Srinivasa Rao, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/40-4/rao.pdf">Heptagonal Numbers in the Lucas Sequence and Diophantine Equations x^2(5x-3)^2 = 20y^2+-16</a>, The Fibonacci Quarterly, Vol. 40, No. 4 (2002), 319-322. %H A292850 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, pp.235-240, (2009). %Y A292850 Cf. A000032, A085787. %Y A292850 Cf. A248506 (triangular Lucas Numbers). %K A292850 nonn,easy,full,fini %O A292850 1,2 %A A292850 _Tomohiro Yamada_, Sep 25 2017