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A167990 Elements in A126988 (by row) that are not 1.

%I A167990 #7 Jan 28 2023 12:34:35
%S A167990 0,2,0,3,0,0,4,2,0,0,5,0,0,0,0,6,3,2,0,0,0,7,0,0,0,0,0,0,8,4,0,2,0,0,
%T A167990 0,0,9,0,3,0,0,0,0,0,0,10,5,0,0,2,0,0,0,0,0,11,0,0,0,0,0,0,0,0,0,0,12,
%U A167990 6,4,3,0,2,0,0,0,0,0,0,13,0,0,0,0,0,0,0,0,0,0,0,0,14,7,0,0,0,0,2,0,0,0,0,0,0,0
%N A167990 Elements in A126988 (by row) that are not 1.
%C A167990 GCD of rows is A014963.
%H A167990 G. C. Greubel, <a href="/A167990/b167990.txt">Rows n = 1..50 of the triangle, flattened</a>
%F A167990 From _G. C. Greubel_, Jan 13 2023: (Start)
%F A167990 T(n, k) = 0 if k = n or (n mod k) != 0, otherwise T(n, k) = n/k.
%F A167990 T(n, 1) = n - [n=1].
%F A167990 T(m*n, n) = m, m >= 2.
%F A167990 Sum_{k=1..n} T(n, k) = A039653(n). (End)
%e A167990 Table begins:
%e A167990    0;
%e A167990    2, 0;
%e A167990    3, 0, 0;
%e A167990    4, 2, 0, 0;
%e A167990    5, 0, 0, 0, 0;
%e A167990    6, 3, 2, 0, 0, 0;
%e A167990    7, 0, 0, 0, 0, 0, 0;
%e A167990    8, 4, 0, 2, 0, 0, 0, 0;
%e A167990    9, 0, 3, 0, 0, 0, 0, 0, 0;
%e A167990   10, 5, 0, 0, 2, 0, 0, 0, 0, 0;
%e A167990   11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0;
%e A167990   12, 6, 4, 3, 0, 2, 0, 0, 0, 0, 0, 0;
%t A167990 Table[If[k==n || Mod[n, k]!=0, 0, n/k], {n,15}, {k,n}]//Flatten (* _G. C. Greubel_, Jan 13 2023 *)
%o A167990 (Magma) [k eq n or (n mod k) ne 0 select 0 else n/k: k in [1..n], n in [1..15]]; // _G. C. Greubel_, Jan 13 2023
%o A167990 (SageMath)
%o A167990 def A167990(n, k):
%o A167990     if (k==n or n%k!=0): return 0
%o A167990     else: return n/k
%o A167990 flatten([[A167990(n, k) for k in (1..n)] for n in (1..12)]) # _G. C. Greubel_, Jan 13 2023
%Y A167990 Cf. A014963, A039653, A126988.
%K A167990 nonn,tabl
%O A167990 1,2
%A A167990 _Mats Granvik_, Nov 16 2009