A316113 a(n) is the least sum of a tuple containing n as an element where the denominator of the sum of reciprocals isn't divisible by any of the prime factors of n.

1, 4, 9, 10, 20, 11, 35, 22, 30, 22, 66, 22, 91, 37, 28, 46, 119, 32, 152, 31, 41, 68, 184, 37, 110, 106, 93, 53, 261, 51, 279, 94, 69, 121, 59, 60, 370, 192, 97, 64, 451, 54, 430, 94, 65, 186, 517, 74, 259, 112, 122, 97, 583, 95, 92, 92, 158, 263, 767, 77, 671

Offset: 1

Author

David A. Corneth, Jul 22 2018

Keywords

• nonn

Examples

			a(12) = 22 because the tuple [3, 3, 4, 12] has the sum of reciprocals 1/3 + 1/3 + 1/4 + 1/12 = 1 of which the denominator is 1 and has no common prime factors with n = 12.
a(25) = 110 because the tuple [5, 5, 25, 25, 50] has the sum of reciprocals 1/5 + 1/5 + 1/25 + 1/25 + 1/50 = 1/2 of which the denominator is 2 and has no common prime factors with n = 25.
		

Links

• Ray Chandler, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A051908, A201644, A201646, A201647, A201648, A201649.

Extensions

More terms from Ray Chandler, Oct 02 2018