The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A229838 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A229838

Consider all primitive 60-degree triangles with sides A < B < C. The sequence gives the values of A.
(history; published version)

#20 by Bruno Berselli at Mon Oct 07 06:17:35 EDT 2013

STATUS

proposed

approved

#19 by Colin Barker at Mon Oct 07 05:59:15 EDT 2013

STATUS

editing

proposed

#18 by Colin Barker at Mon Oct 07 05:59:01 EDT 2013

FORMULA

Empirical g.f.: -x*(x^5-x^4-x^3-2*x^2-2*x-3) / ((x-1)^2*(x^4+x^3+x^2+x+1)).

STATUS

approved

editing

#17 by T. D. Noe at Sun Oct 06 13:50:37 EDT 2013

STATUS

proposed

approved

#16 by Colin Barker at Sat Oct 05 03:12:18 EDT 2013

STATUS

editing

proposed

#15 by Colin Barker at Sat Oct 05 03:11:57 EDT 2013

LINKS

Wikipedia, <a href="https://en.wikipedia.org/wiki/Integer_triangle">Integer triangle</a>

STATUS

proposed

editing

#14 by Colin Barker at Fri Oct 04 04:07:55 EDT 2013

STATUS

editing

proposed

#13 by Colin Barker at Fri Oct 04 04:07:47 EDT 2013

PROG

if(a2=m*m-n*n<=amax, s=concat(s, a2=m*m-n*n))

STATUS

proposed

editing

#12 by Colin Barker at Fri Oct 04 03:56:59 EDT 2013

STATUS

editing

proposed

#11 by Colin Barker at Fri Oct 04 03:56:26 EDT 2013

PROG

\\ e.g. pt60a(3025) gives [3, 5, 7, 8, 9, 11, 13, 15, 16, 17, 19, 21, 23, 24, 25, 27, 29]