A334024
Numbers k such that s(k) = s(k+1), where s(k) is the sum of unitary divisors of k that are larger than sqrt(k) (A334023).
Original entry on oeis.org
24752, 101972, 14257705
Offset: 1
24752 is a term since A334023(24752) = A334023(24753) = 33896.
-
s[n_] := DivisorSum[n, # &, #^2 > n && CoprimeQ[#, n/#] &]; Select[Range[1.5*10^7], s[#] == s[# + 1] &]
A348628
Numbers k such that k and k+1 have the same sum of nonexponential divisors (A160135).
Original entry on oeis.org
1, 2, 3, 4, 15, 44, 674, 478899
Offset: 1
2 is a term since A160135(2) = A160135(3) = 1.
15 is a term since A160135(15) = A160135(16) = 9.
-
esigma[n_] := Times @@ (Sum[First[#]^d, {d, Divisors[Last[#]]}] &) /@ FactorInteger[n]; s[1] = 1; s[n_] := DivisorSigma[1, n] - esigma[n]; Select[Range[500000], s[#] == s[# + 1] &]
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