216 Jean-Marie De Koninck
41 067
the eighth odd number n 1 such that γ(n)|σ(n) (see the number 135).
41 154
the sixth and largest solution of φ(n) =
γ(n)2
(see the number 108).
41 282
the only number 2 which is equal to the sum of the factorials of its digits in
base 9: here 41 282 = [6, 2, 5, 5, 8]9 = 6! + 2! + 5! + 5! + 8! (see also the numbers
145 and 40 472).
41 616 (=
2042)
the fourth triangular number which is also a perfect square: here
41 616 =
288(288+1)
2
= 2042 (see the number 36).
41 908
the number of integer zeros of M(x) :=
n≤x
µ(n) which are located in the in-
terval [1, 108] (see the number 92).
42 209
the
19th
prime number pk such that p1p2 . . . pk + 1 is prime (see the number
379).
42 336
(=25
·
33
·
72)
the fourth Erd˝ os-Nicolas number (see the number 2 016).
42 719
the median value of the third prime factor of a number (see the number 37).
43 217 (= 23 · 1879)
the number n which allows the sum
m≤n
Ω(m)=2
1
m
to exceed 3 (see the number 871).
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