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Revision History for A051875

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A051875

23-gonal numbers: a(n) = n(21n-19)/2.
(history; published version)

#53 by Alois P. Heinz at Mon Feb 06 06:15:54 EST 2023

STATUS

proposed

approved

#52 by Nikolaos Pantelidis at Mon Feb 06 06:12:45 EST 2023

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editing

proposed

#51 by Nikolaos Pantelidis at Mon Feb 06 06:12:29 EST 2023

FORMULA

E.g.f.: exp(x)*(x + 21*x^2/2). - Nikolaos Pantelidis, Feb 06 2023

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approved

editing

#50 by Harvey P. Dale at Mon Aug 01 13:37:13 EDT 2022

STATUS

editing

approved

#49 by Harvey P. Dale at Mon Aug 01 13:37:09 EDT 2022

MATHEMATICA

PolygonalNumber[23, Range[0, 40]] (* Harvey P. Dale, Aug 01 2022 *)

STATUS

approved

editing

#48 by Joerg Arndt at Fri Jan 22 03:29:31 EST 2021

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reviewed

approved

#47 by Michel Marcus at Fri Jan 22 03:20:48 EST 2021

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proposed

reviewed

#46 by Amiram Eldar at Fri Jan 22 03:09:41 EST 2021

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editing

proposed

#45 by Amiram Eldar at Fri Jan 22 03:04:43 EST 2021

REFERENCES

A. Albert H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, p. 189.

FORMULA

Product_{n>=2} (1 - 1/a(n)) = 21/23. - Amiram Eldar, Jan 22 2021

STATUS

approved

editing

#44 by R. J. Mathar at Thu Jul 28 09:16:10 EDT 2016

STATUS

editing

approved