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A362936
a(n) = A000982(n) - A362931(n).
2
0, 0, 2, 4, 8, 8, 14, 20, 28, 36, 46, 52, 64, 76, 86, 100, 116, 128, 146, 160, 180, 200, 222, 240, 264, 288, 314, 336, 364, 384, 414, 444, 476, 508, 538, 568, 604, 640, 678, 712, 752, 784, 826, 868, 904, 948, 994, 1036, 1084, 1132, 1182, 1232, 1284, 1332, 1386, 1436, 1492, 1548, 1606, 1652, 1712
OFFSET
1,3
COMMENTS
a(n) = (number of pairs (i,j) in [1..n] X [1..n] with integral arithmetic mean) - (number of pairs (i,j) in [1..n] X [1..n] with integral harmonic mean).
LINKS
PROG
(Python)
def A362936(n): return ((n-1)**2>>1)-(sum(1 for x in range(1, n+1) for y in range(1, x) if not (x*y<<1)%(x+y))<<1) # Chai Wah Wu, Aug 29 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Aug 28 2023
STATUS
approved