A369663 Numbers k of the form 4m+3, whose arithmetic derivative k' is of the form 4u+2, and k' has an even number of prime factors.

375, 459, 783, 819, 875, 1071, 1107, 1155, 1375, 1395, 1715, 1911, 1935, 1995, 2223, 2275, 2375, 2499, 2619, 2655, 2695, 2727, 2875, 2907, 2943, 3003, 3051, 3135, 3195, 3255, 3315, 3519, 3575, 3627, 3699, 3843, 3927, 3975, 4059, 4459, 4515, 4671, 4815, 4887, 4935, 4959, 5187, 5247, 5375, 5415, 5607, 5635, 5655

Offset: 1

Author

Antti Karttunen, Feb 06 2024

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Intersection of A004767 and A369661.

Subsequence of A369666.

Cf. A003415, A351228.

Programs

PARI

A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
isA369663(n) = if(3!=(n%4), 0, my(d=A003415(n)); (2==(d%4) && !(bigomega(d)%2)));