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A328962
Smallest k such that sigma_0(k) - omega(k) * nu(k) = n, and 0 if none exists, where sigma_0 = A000005, nu = A001221, omega = A001222.
6
30, 6, 1, 72, 144, 216, 576, 360, 2304, 840, 720, 1728, 1080, 1260, 147456, 6912, 1800, 2160, 2359296, 4620, 9437184, 2520, 3600, 110592, 6480, 5400, 46656, 6300, 7200, 5040, 9240, 12960, 17280, 7560, 10800, 7077888, 186624, 10080, 13860
OFFSET
-1,1
EXAMPLE
The sequence of terms together with their prime signatures begins:
30: (1,1,1)
6: (1,1)
1: ()
72: (3,2)
144: (4,2)
216: (3,3)
576: (6,2)
360: (3,2,1)
2304: (8,2)
840: (3,1,1,1)
720: (4,2,1)
1728: (6,3)
1080: (3,3,1)
1260: (2,2,1,1)
147456: (14,2)
6912: (8,3)
1800: (3,2,2)
2160: (4,3,1)
MATHEMATICA
dat=Table[DivisorSigma[0, n]-PrimeOmega[n]*PrimeNu[n], {n, 1000}];
Table[Position[dat, i][[1, 1]], {i, First[Split[Union[dat], #2==#1+1&]]}]
CROSSREFS
Positions of first appearances in A328958.
Sequence in context: A255865 A299195 A040878 * A073460 A036390 A040879
KEYWORD
nonn
AUTHOR
Gus Wiseman, Nov 02 2019
STATUS
approved