OFFSET
1,4
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
Michael De Vlieger, Log log scatterplot of a(n), n = 1..2^18.
FORMULA
EXAMPLE
Table showing perfect powers in row n of A162306 for n <= 36 such that a(n) > 1:
4: {1, 4}
6: {1, 4}
8: {1, 4, 8}
9: {1, 9}
10: {1, 4, 8}
12: {1, 4, 8, 9}
14: {1, 4, 8}
15: {1, 9}
16: {1, 4, 8, 16}
18: {1, 4, 8, 9, 16}
20: {1, 4, 8, 16}
30: {1, 4, 8, 9, 16, 25, 27}
36: {1, 4, 8, 9, 16, 27, 32, 36}
MATHEMATICA
Table[Which[PrimeQ[n], 0,
PrimePowerQ[n], FactorInteger[n][[1, -1]] - 1,
True, Count[Range[n],
_?(And[Divisible[n, Times @@ #[[All, 1]]],
GCD @@ #[[All, -1]] > 1] &@ FactorInteger[#]} &)] ], {n, 120}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Michael De Vlieger, Oct 02 2024
STATUS
approved