A090541 a(n) = floor((Sum_{r=1..n} r)*(Sum_{r=1..n} 1/r)).

1, 4, 11, 20, 34, 51, 72, 97, 127, 161, 199, 242, 289, 341, 398, 459, 526, 597, 674, 755, 842, 933, 1030, 1132, 1240, 1352, 1470, 1594, 1723, 1857, 1997, 2142, 2293, 2450, 2612, 2780, 2953, 3132, 3317, 3508, 3704, 3907, 4115, 4328, 4548, 4774, 5006, 5243

Offset: 1

Author

Amarnath Murthy, Dec 09 2003

Keywords

• nonn

Comments

For large n, a(n) = floor(n*(n+1)/2)*(log(n) + 0.5772...,(Euler's constant)).

Crossrefs

Cf. A052488.

Programs

Maple

a:=n->floor(sum(k,k=1..n)*sum(1/k,k=1..n)):seq(a(n),n=1..56); # Emeric Deutsch, Apr 18 2005

PARI

a(n) = floor((n*(n+1)/2)*sum(k=1, n, 1/k)); \\ Michel Marcus, Aug 18 2019

Extensions

More terms from Emeric Deutsch, Apr 18 2005