A049791 a(n) = Sum_{k=1..n} T(n,k), array T as in A049790.

1, 5, 14, 30, 54, 91, 137, 202, 280, 380, 492, 644, 799, 994, 1212, 1471, 1735, 2071, 2400, 2811, 3232, 3709, 4190, 4804, 5380, 6046, 6739, 7535, 8297, 9246, 10115, 11153, 12184, 13320, 14458, 15839, 17074, 18493, 19931, 21583, 23100, 24942, 26609, 28564, 30517, 32593, 34585, 37048, 39231, 41735, 44187, 46911

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A049790, A049792, A049793, A049794, A049795, A049796.

Programs

GAP

List([1..60], n-> Sum([1..n], k-> Sum([1..k], j-> Int(n/Int(k/j)) ))); # G. C. Greubel, Dec 10 2019

Magma

[ &+[(&+[Floor(n/Floor(k/j)): j in [1..k]]): k in [1..n]] n in [1..60]]; // G. C. Greubel, Dec 10 2019

Maple

seq( add(add(floor(n/floor(k/j)), j=1..k), k=1..n), n=1..60); # G. C. Greubel, Dec 10 2019

Mathematica

Table[Sum[Sum[Floor[n/Floor[k/j]], {j, k}], {k, n}], {n, 1, 60}] (* G. C. Greubel, Dec 10 2019 *)

PARI

a(n) = sum(k=1,n, sum(j=1,k, n\(k\j) ));
vector(60, n, a(n)) \\ G. C. Greubel, Dec 10 2019

Sage

[sum(sum(floor(n/floor(k/j)) for j in (1..k)) for k in (1..n)) for n in (1..60)] # G. C. Greubel, Dec 10 2019

Extensions

Terms a(40) onward added by G. C. Greubel, Dec 10 2019