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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A126695 Numbers that can be expressed as the ratio between the product and the sum of n consecutive numbers with n>1.

Original entry on oeis.org

1, 5, 8, 16, 20, 21, 33, 36, 40, 56, 65, 85, 96, 120, 133, 161, 176, 180, 208, 224, 225, 261, 280, 320, 341, 385, 408, 432, 456, 481, 533, 560, 616, 645, 705, 736, 756, 800, 833, 901, 936, 1008, 1045, 1120, 1121, 1152, 1160, 1232, 1240
Offset: 1

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Author

Paolo P. Lava and Giorgio Balzarotti, Feb 15 2007, corrected Feb 20 2007 and Mar 06 2007

Keywords

Examples

			224 = 4*5*6*7*8/(4+5+6+7+8)
225 = 25*26*27/(25+26+27)
5544 = 11*12*13*14*15/(11+12+13+14+15)
		

Crossrefs

Formula

Number = Product_{i=a..a+n-1} i / Sum_{i=a..a+n-1} i with a, n > 1
Integer values of (n+1)*binomial(a+n,a-1)/Sum_{i=0..n-1}(a+i) with a, n > 1
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