The On-Line Encyclopedia of Integer Sequences (OEIS)

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A000384

Hexagonal numbers: a(n) = n*(2*n-1).
(history; published version)

#472 by Charles R Greathouse IV at Sun Feb 16 08:32:21 EST 2025

LINKS

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/CocktailPartyGraph.html">Cocktail Party Graph</a>.

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/DominatingSet.html">Dominating Set</a>.

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/HexagonalNumber.html">Hexagonal Number</a>.

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/MaximalIrredundantSet.html">Maximal Irredundant Set</a>.

Discussion

Sun Feb 16

08:32

OEIS Server: https://oeis.org/edit/global/3014

#471 by Michael De Vlieger at Wed Jan 08 12:49:30 EST 2025

STATUS

reviewed

approved

#470 by Stefano Spezia at Wed Jan 08 12:48:34 EST 2025

STATUS

proposed

reviewed

#469 by Michel Marcus at Wed Jan 08 12:38:54 EST 2025

STATUS

editing

proposed

#468 by Michel Marcus at Wed Jan 08 12:38:04 EST 2025

COMMENTS

Let Hex(n)=hexagonal number, T(n)=triangular number, then Hex(n)=T(n)+3*T(n-1). - Vincenzo Librandi, Nov 10 2010

FORMULA

a(n) = T(n) + 3*T(n-1), where T(n) is the n-th triangular number. - Vincenzo Librandi, Nov 10 2010

STATUS

approved

editing

#467 by Russ Cox at Sun Jan 05 19:51:31 EST 2025

LINKS

C. K. Cook and M. R. Bacon, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Papers1/52-4/CookBacon4292014.pdf">Some polygonal number summation formulas</a>, Fib. Q., 52 (2014), 336-343.

Discussion

Sun Jan 05

19:51

OEIS Server: https://oeis.org/edit/global/3012

#466 by Michael De Vlieger at Tue Dec 10 12:32:35 EST 2024

STATUS

proposed

approved

#465 by Michel Marcus at Tue Dec 10 12:31:26 EST 2024

STATUS

editing

proposed

#464 by Michel Marcus at Tue Dec 10 12:31:20 EST 2024

LINKS

Milan Janjic, <a href="httphttps://wwwold.pmf.pmfblunibl.org/janjicwp-content/uploads/2017/10/enumfor.pdf">Two Enumerative Functions</a>.

STATUS

proposed

editing

#463 by Michael De Vlieger at Tue Dec 10 12:16:57 EST 2024

STATUS

editing

proposed