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A348392
Row sums of the irregular triangle A348389.
3
2, 5, 13, 18, 36, 43, 67, 85, 115, 126, 186, 199, 241, 286, 350, 367, 457, 476, 576, 639, 705, 728, 896, 946, 1024, 1105, 1245, 1274, 1484, 1515, 1675, 1774, 1876, 1981, 2269, 2306, 2420, 2537, 2817
OFFSET
2,1
FORMULA
a(n) = Sum_{m=1.. A002541(n)} A348389(n, m), for n >= 2.
a(n) = A143127(n) - A000217(n).
a(n) = A348391(n) - A153485(n).
EXAMPLE
n = 4: Compare the row of an array with all multiples of k <= n, for k = 1,2, ..., n with the row of A348389:
All multiples of k <= 4 for k = 1..4: [1 2 3 4|2 4|3|4] with row sum A143127(4) = 23.
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).
Also: a(4) = A348391(4) - A153485(4) = 18 - 5 = 13.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Oct 31 2021
STATUS
approved