The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A072502 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A072502

Numbers that are run sums (trapezoidal, the difference between two triangular numbers) in exactly 3 ways.
(history; published version)

#50 by Michel Marcus at Thu Feb 18 02:36:10 EST 2021

STATUS

reviewed

approved

#49 by Joerg Arndt at Thu Feb 18 02:28:12 EST 2021

STATUS

proposed

reviewed

#48 by Amiram Eldar at Thu Feb 18 02:07:31 EST 2021

STATUS

editing

proposed

#47 by Amiram Eldar at Thu Feb 18 02:05:36 EST 2021

LINKS

Ron Knott, <a href="http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/runsums/index.html">Introducing Runsums - a sum of consecutive integers</a>.

#46 by Amiram Eldar at Thu Feb 18 02:03:53 EST 2021

LINKS

T. Verhoeff, <a href="http://www.cs.uwaterloo.ca/journals/JIS/trapzoid.html">Rectangular and Trapezoidal Arrangements</a>, J. Integer Sequences, Vol. 2, (1999, ), Article #99.1.6.

#45 by Amiram Eldar at Thu Feb 18 02:03:13 EST 2021

FORMULA

Sum_{n>=1} 1/a(n) = 2 * Sum_{p odd prime} 1/p^2 = 2 * A085548 - 1/2 = 0.404494... - Amiram Eldar, Feb 18 2021

CROSSREFS

Cf. A001227, A001248, A038547, A038550, A085548, A237593, A266531, A279387.

STATUS

approved

editing

#44 by N. J. A. Sloane at Wed Dec 02 18:07:54 EST 2020

STATUS

proposed

approved

#43 by Omar E. Pol at Tue Dec 01 09:23:52 EST 2020

STATUS

editing

proposed

#42 by Omar E. Pol at Tue Dec 01 09:23:34 EST 2020

COMMENTS

Column 3 of A266531. - Omar E. Pol, Dec 01 2020

CROSSREFS

Cf. A001227, A001248, A038547, A038550, A237593, A266531, A279387.

STATUS

approved

editing

#41 by N. J. A. Sloane at Tue Dec 01 01:45:35 EST 2020

STATUS

editing

approved