The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A000566 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A000566

Heptagonal numbers (or 7-gonal numbers): n*(5*n-3)/2.
(history; published version)

#223 by N. J. A. Sloane at Sat Sep 07 15:43:31 EDT 2024

STATUS

proposed

approved

#222 by Stefano Spezia at Sat Sep 07 14:59:15 EDT 2024

STATUS

editing

proposed

#221 by Stefano Spezia at Sat Sep 07 13:45:31 EDT 2024

LINKS

Bir Kafle, Florian Luca , and Alain Togbé, <a href="https://doi.org/10.33039/ami.2020.09.002">Pentagonal and heptagonal repdigits</a>, Annales Mathematicae et Informaticae, pp. 137-145.

#220 by Stefano Spezia at Sat Sep 07 12:27:31 EDT 2024

LINKS

Bir Kafle, Florian Luca and Alain Togbé, <a href="https://doi.org/10.33039/ami.2020.09.002">Pentagonal and heptagonal repdigits</a>, Annales Mathematicae et Informaticae. , pp. 137-145.

#219 by Stefano Spezia at Sat Sep 07 12:26:59 EDT 2024

LINKS

Simon Plouffe, <a href="/A000051/a000051_2.pdf">1031 Generating Functions</a>, Appendix to Thesis, Montreal, 1992.

Omar E. Pol, <a href="http://www.polprimos.com/imagenespub/polnum01.jpg">Illustration of initial terms of A000217, A000290, A000326, A000384, A000566, A000567</a>.

#218 by Stefano Spezia at Sat Sep 07 12:26:36 EDT 2024

LINKS

INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=341">Encyclopedia of Combinatorial Structures 341</a>.

Leo Tavares, <a href="/A000566/a000566.jpg">Illustration</a>.

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HeptagonalNumber.html">Heptagonal Number</a>.

<a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>.

#217 by Stefano Spezia at Sat Sep 07 09:37:21 EDT 2024

REFERENCES

David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 123.

STATUS

approved

editing

#216 by R. J. Mathar at Mon Apr 22 07:37:44 EDT 2024

STATUS

editing

approved

#215 by R. J. Mathar at Mon Apr 22 07:37:29 EDT 2024

COMMENTS

Comment from Ken Rosenbaum, Dec 02 2009: if you multiply the terms of this sequence by 40 and add 9, you get A017354, which is the list of squares of all whole numbers ending in 7 (this is easy to prove).

FORMULA

40*a(n)+ 9 = A017354(n-1). - Ken Rosenbaum, Dec 02 2009.

STATUS

approved

editing

#214 by Alois P. Heinz at Mon Oct 23 11:15:51 EDT 2023

STATUS

proposed

approved