A390533 Non-semiprime solutions m to m'' = m'+1, where m' and m'' are the first and the second arithmetic derivatives of m.

1935, 35832472407, 130475371123, 277928774803, 1967073078403, 3096293268967, 639806241140811, 6633813463595167, 11099679950675131, 22860089823670423, 160288778427770791, 189455881727134807, 221740666337812387, 305106220213253047, 489313550320498927

Offset

1,1

Comments

Equivalently, non-semiprime solutions for m' = q, where q is a Giuga number (A007850). Terms a(101) and on are solutions to m' = A007850(k) with k >= 10.

All solutions are listed in A189639.

Links

Max Alekseyev, Table of n, a(n) for n = 1..100

Crossrefs

Subsequence of A189639.

Cf. A003415, A007850, A366890, A377987, A377992, A387956.

Sequence in context: A277943 A251945 A340843 * A270265 A237010 A256765

Adjacent sequences: A390530 A390531 A390532 * A390534 A390535 A390536

Keyword

nonn,hard

Author

Max Alekseyev, Nov 09 2025

Status

approved