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- #!/usr/bin/ruby
- # Number k such that tau(k) equals the number of solutions to sigma(x) = k.
- # Sequence related to:
- # https://oeis.org/A305058
- # Known terms:
- # 1, 31, 24192, 57600, 430080, 1059840, 1080000, 1436400, 1446336, 1676160, 1713600, 1956864, 2045952, 2086560, 2213568, 2301696, 2673216, 2688336, 3566592, 3618816, 3935232, 4069440, 4584960, 5296896, 5673024, 5692032, 5695488, 5760720
- for k in (1..5760720) {
- if (k.inverse_sigma.len == k.sigma0) {
- print(k, ", ")
- }
- }
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