A049795 a(n) = T(n,n-3), array T as in A049790.

1, 2, 3, 4, 7, 14, 18, 29, 35, 49, 57, 74, 84, 105, 115, 140, 155, 180, 195, 228, 244, 278, 296, 332, 356, 397, 416, 460, 487, 534, 559, 612, 637, 691, 722, 779, 814, 872, 901, 968, 1007, 1073, 1107, 1180, 1218, 1292, 1333, 1407

Offset: 4

Author

Clark Kimberling

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 4..1000

Crossrefs

Cf. A049790, A049791, A049792, A049793, A049794, A049796.

Programs

GAP

a:= function(n)
    if n<7 then return n-3;
    else return Sum([1..n-6], j-> Int((n-3)/Int((n-6)/j)) );
    fi; end;
List([4..60], n-> a(n) ); # G. C. Greubel, Dec 10 2019

Magma

[n lt 7 select n-3 else (&+[Floor((n-3)/Floor((n-6)/j)): j in [1..n-6]]): n in [4..60]]; // G. C. Greubel, Dec 10 2019

Maple

seq( `if`(n<7, n-3, add(floor((n-3)/floor((n-6)/j)), j=1..n-6)), n=4..60); # G. C. Greubel, Dec 10 2019

Mathematica

Table[If[n<7, n-3, Sum[Floor[(n-3)/Floor[(n-6)/j]], {j,n-6}]], {n,4,60}] (* G. C. Greubel, Dec 10 2019 *)

PARI

a(n) = if(n<7, n-3, sum(j=1,n-6, (n-3)\((n-6)\j)) );
vector(60, n, a(n+3) ) \\ G. C. Greubel, Dec 10 2019

Sage

def a(n):
    if (n<7): return n-3
    else: return sum(floor((n-3)/floor((n-6)/j)) for j in (1..n-6))
[a(n) for n in (4..60)] # G. C. Greubel, Dec 10 2019