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A049795 a(n) = T(n,n-3), array T as in A049790. 7

%I #9 Sep 08 2022 08:44:58

%S 1,2,3,4,7,14,18,29,35,49,57,74,84,105,115,140,155,180,195,228,244,

%T 278,296,332,356,397,416,460,487,534,559,612,637,691,722,779,814,872,

%U 901,968,1007,1073,1107,1180,1218,1292,1333,1407

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

%H G. C. Greubel, <a href="/A049795/b049795.txt">Table of n, a(n) for n = 4..1000</a>

%p 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

%t 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 *)

%o (PARI) a(n) = if(n<7, n-3, sum(j=1,n-6, (n-3)\((n-6)\j)) );

%o vector(60, n, a(n+3) ) \\ _G. C. Greubel_, Dec 10 2019

%o (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

%o (Sage)

%o def a(n):

%o if (n<7): return n-3

%o else: return sum(floor((n-3)/floor((n-6)/j)) for j in (1..n-6))

%o [a(n) for n in (4..60)] # _G. C. Greubel_, Dec 10 2019

%o (GAP)

%o a:= function(n)

%o if n<7 then return n-3;

%o else return Sum([1..n-6], j-> Int((n-3)/Int((n-6)/j)) );

%o fi; end;

%o List([4..60], n-> a(n) ); # _G. C. Greubel_, Dec 10 2019

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

%K nonn

%O 4,2

%A _Clark Kimberling_

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Last modified May 6 10:12 EDT 2024. Contains 372293 sequences. (Running on oeis4.)