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A333292

Triangle read by rows: T(m,n) = Sum_{ 1 <= i <= m, 1 <= j <= n, gcd(i,j)=1 } i*j, for 1 <= n <= m.

1, 3, 5, 6, 14, 23, 10, 18, 39, 55, 15, 33, 69, 105, 155, 21, 39, 75, 111, 191, 227, 28, 60, 117, 181, 296, 374, 521, 36, 68, 149, 213, 368, 446, 649, 777, 45, 95, 176, 276, 476, 554, 820, 1020, 1263, 55, 105, 216, 316, 516, 594, 930, 1130, 1463, 1663, 66, 138, 282, 426, 681, 825, 1238, 1526, 1958, 2268, 2873

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OFFSET

1,2

COMMENTS

The last two diagonals are A333293, Sum_{k=1..n-1} k^2*phi(k) + n^2*phi(n)/2, and A319087, Sum_{k=1..n} k^2*phi(k), where phi = A000010. Is there a similar formula for the general term?

LINKS

Alois P. Heinz, Rows n = 1..141, flattened

EXAMPLE

Triangle begins:

3, 5,

6, 14, 23,

10, 18, 39, 55,

15, 33, 69, 105, 155,

21, 39, 75, 111, 191, 227,

28, 60, 117, 181, 296, 374, 521,

36, 68, 149, 213, 368, 446, 649, 777,

45, 95, 176, 276, 476, 554, 820, 1020, 1263,