A227107 Numerators of harmonic mean H(n,4), n >= 0.

0, 8, 8, 24, 4, 40, 24, 56, 16, 72, 40, 88, 6, 104, 56, 120, 32, 136, 72, 152, 20, 168, 88, 184, 48, 200, 104, 216, 7, 232, 120, 248, 64, 264, 136, 280, 36, 296, 152, 312, 80, 328, 168, 344, 22, 360, 184, 376, 96, 392, 200, 408, 52, 424, 216

Offset: 0

Author

Wolfdieter Lang, Jul 01 2013

Keywords

• nonn
• frac
• easy

Comments

a(n) = numerator(H(n,4)) = numerator(8*n/(n+4)), n>=0, with H(n,4) the harmonic mean of n and 4.

The corresponding denominators are given in A000265(n+4), n >= 0.

a(n+4), n>=0, is the fourth column (m=4) of the triangle A227041.

Examples

			The rationals H(n,4) begin: 0, 8/5, 8/3, 24/7, 4, 40/9, 24/5, 56/11, 16/3, 72/13, 40/7, 88/15, 6, 104/17, 56/9, 120/19, ...
		

Crossrefs

Cf. A227041(n+4,4), A227140(n+8) (denominators), n >= 0.

Formula

a(n) = numerator(8*n/(n+4)), n >= 0.

a(n) = 8*n/gcd(n+4,8*n) = 8*n/gcd(n+4,32), n >= 0.