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Numbers that can be expressed as the ratio between the product and the sum of n consecutive numbers with n>1.
2

%I #6 Feb 29 2024 17:21:36

%S 1,5,8,16,20,21,33,36,40,56,65,85,96,120,133,161,176,180,208,224,225,

%T 261,280,320,341,385,408,432,456,481,533,560,616,645,705,736,756,800,

%U 833,901,936,1008,1045,1120,1121,1152,1160,1232,1240

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

%F Number = Product_{i=a..a+n-1} i / Sum_{i=a..a+n-1} i with a, n > 1

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

%e 224 = 4*5*6*7*8/(4+5+6+7+8)

%e 225 = 25*26*27/(25+26+27)

%e 5544 = 11*12*13*14*15/(11+12+13+14+15)

%Y Cf. A370601

%K easy,nonn

%O 1,2

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Feb 15 2007, corrected Feb 20 2007 and Mar 06 2007