A227307 Numbers k that divide sigma(k) - sigma(k-1).
2, 6, 15, 19, 207, 958, 1335, 1365, 1635, 2686, 2975, 3201, 4365, 4536, 8586, 14842, 16120, 18874, 19359, 20146, 24958, 33999, 36567, 42819, 53580, 56565, 64666, 74919, 79827, 79834, 84135, 92686, 109215, 111507, 116938, 122074, 138238, 147455, 161002, 162603, 166935
Offset: 1
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
With[{m = 200000}, 1 + Position[Differences[DivisorSigma[1, Range[m]]]/Range[2, m], ?IntegerQ] // Flatten] (* _Amiram Eldar, Dec 31 2024 *) -
PARI
list(lim) = {my(s1 = 1, s2); for(k = 2, lim, s2 = sigma(k); if(!((s2-s1) % k), print1(k, ", ")); s1 = s2);} \\ Amiram Eldar, Dec 31 2024