A110663 - OEIS

A110663

Triangle read by rows: T(n,k) = Sum_{j=k..n} phi(j) (1<=k<=n), where phi is Euler's totient function.

1, 2, 1, 4, 3, 2, 6, 5, 4, 2, 10, 9, 8, 6, 4, 12, 11, 10, 8, 6, 2, 18, 17, 16, 14, 12, 8, 6, 22, 21, 20, 18, 16, 12, 10, 4, 28, 27, 26, 24, 22, 18, 16, 10, 6, 32, 31, 30, 28, 26, 22, 20, 14, 10, 4, 42, 41, 40, 38, 36, 32, 30, 24, 20, 14, 10, 46, 45, 44, 42, 40, 36, 34, 28, 24, 18, 14, 4

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OFFSET

1,2

LINKS

Indranil Ghosh, Rows 1..100, flattened

FORMULA

T(n,n) = phi(n) = A000010(n) = number of numbers <=n and relatively prime to n.

T(n,1) = Sum_{j=1..n} phi(j) = A002088(n).

EXAMPLE

T(5,3) = 8 because phi(3)+phi(4)+phi(5) = 2+2+4 = 8.

Triangle begins:

2,1;