cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A156736 Signed greedy Egyptian fraction for Pi/2.

Original entry on oeis.org

1, 2, 14, -1582, -7497258, 303297921775458, -2646995089135122277190614296178, 82888930564911423983289917045230098319343306166666586941750246
Offset: 0

Views

Author

Jaume Oliver Lafont, Feb 14 2009

Keywords

Comments

The second and fourth convergents of Pi (22/7 and 355/113) appear when truncating the series to three and four terms.

Examples

			1+1/2+1/14=11/7=(1/2)(22/7)
1+1/2+1/14-1/1582=355/226=(1/2)(355/113)

Links

Crossrefs

Cf. A001466, A156269, A156618.
Cf. A156750. [From Jaume Oliver Lafont, Mar 03 2009]

Programs

  • PARI
    x=Pi/2; for (k=0,7, d=round(1/x); x=x-1/d; print1(d,", "))

Formula

Sum(n>=0,1/a(n))=Pi/2.
a(n) = 2*A001467(n+1). - R. J. Mathar, Apr 02 2011
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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