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Row sums of the irregular triangle A348389.
3

%I #7 Nov 27 2021 11:58:41

%S 2,5,13,18,36,43,67,85,115,126,186,199,241,286,350,367,457,476,576,

%T 639,705,728,896,946,1024,1105,1245,1274,1484,1515,1675,1774,1876,

%U 1981,2269,2306,2420,2537,2817

%N Row sums of the irregular triangle A348389.

%F a(n) = Sum_{m=1.. A002541(n)} A348389(n, m), for n >= 2.

%F a(n) = A143127(n) - A000217(n).

%F a(n) = A348391(n) - A153485(n).

%e n = 4: Compare the row of an array with all multiples of k <= n, for k = 1,2, ..., n with the row of A348389:

%e All multiples of k <= 4 for k = 1..4: [1 2 3 4|2 4|3|4] with row sum A143127(4) = 23.

%e A348389 row 4: [2 3 4|4] with 1, 2, 3 and 4 missing: row sum is 23 - 4*5/2 = 13. Hence a(4) = A143127(4) - A000217(4).

%e Also: a(4) = A348391(4) - A153485(4) = 18 - 5 = 13.

%Y Cf. A000217, A002541, A143127, A348389.

%K nonn,easy

%O 2,1

%A _Wolfdieter Lang_, Oct 31 2021