[seqfan] A106464
israel at math.ubc.ca
israel at math.ubc.ca
Fri May 11 00:42:57 CEST 2018
Can somebody make sense out of A106464?
A106464 Diagonal sums of number triangle A029578.
(but A029578 is not a triangle!)
Data are
1, 1, 2, 3, 3, 4, 6, 6, 5, 11, 6, 9, 15, 12, 8, 18, 9, 21, 22, 15,
11, 32, 20, 18, 27, 31, 14, 45, 15, 32, 36, 24, 41, 57, 18, 27, 43, 60, 20,
66, 21, 51, 72, 33, 23, 84, 42, 60, 57, 61, 26, 81, 67, 88, 64, 42, 29,
135, 30, 45, 105
with offset 0. There is a formula given:
a(n)=sum{k=0..floor(n/2), gcd(n-k+1, k+1)}
but that doesn't match the Data: it would produce
1, 1, 3, 2, 6, 3, 8, 6, 11, 5, 17, 6, 16, 15, 20, 8, 27, 9, 31, 22, 26, 11,
44, 20, 31, 27, 45, 14, 60, 15, 48, 36, 41, 41, 75, 18, 46, 43, 80, 20, 87,
21, 73, 72, 56, 23, 108, 42, 85, 57, 87, 26, 108, 67, 116, 64, 71, 29, 165,
30, 76
which is A060992 (without the first term 0).
Cheers,
Robert
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