A361671 Squarefree part of the n-th tetrahedral number.
1, 1, 10, 5, 35, 14, 21, 30, 165, 55, 286, 91, 455, 35, 170, 51, 969, 285, 1330, 385, 1771, 506, 23, 26, 13, 91, 406, 1015, 4495, 310, 341, 374, 6545, 1785, 7770, 2109, 9139, 2470, 2665, 2870, 12341, 3311, 14190, 3795, 16215, 1081, 94, 1, 17, 221, 23426, 689, 2915, 770, 7315, 7714, 32509, 8555
Offset: 1
Crossrefs
Programs
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PARI
a(n) = core(n*(n+1)*(n+2)/6); \\ Michel Marcus, Mar 22 2023
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Python
from sympy.ntheory.factor_ import core def A361671(n): return core(n*(n*(n + 3) + 2)//6) # Chai Wah Wu, Mar 20 2023