%I #9 Jan 02 2017 01:58:16
%S 1,1,1,2,1,2,2,2,2,2,4,2,4,2,4,2,4,4,4,4,2,6,2,8,4,8,2,6,4,6,4,8,8,4,
%T 6,4,6,4,12,4,16,4,12,4,6,4,6,8,12,8,8,12,8,6,4,10,4,12,8,24,4,24,8,
%U 12,4,10
%N Triangle T(n,m) read by rows: T(n,m) = phi(n - m + 1) * phi(m + 1).
%C Row sums are 1, 2, 5, 8, 16, 20, 36, 44, 68, 76, 120, ...
%F T(n,m) = phi(n - m + 1) * phi(m + 1).
%e {1},
%e {1, 1},
%e {2, 1, 2},
%e {2, 2, 2, 2},
%e {4, 2, 4, 2, 4},
%e {2, 4, 4, 4, 4, 2},
%e {6, 2, 8, 4, 8, 2, 6},
%e {4, 6, 4, 8, 8, 4, 6, 4},
%e {6, 4, 12, 4, 16, 4, 12, 4, 6},
%e {4, 6, 8, 12, 8, 8, 12, 8, 6, 4},
%e {10, 4, 12, 8, 24, 4, 24, 8, 12, 4, 10}
%t T[n_, m_] = EulerPhi[n - m + 1]*EulerPhi[m + 1]; Table[Table[T[n, m], {m, 0, n}], {n, 0, 10}]; Flatten[%]
%Y Cf. A000010.
%K nonn,tabl
%O 1,4
%A _Roger L. Bagula_ and _Gary W. Adamson_, Aug 25 2008
|