A349870 Numbers k such that k and k+1 are both nobly abundant numbers (A349758).

735, 819, 1035, 1196, 1274, 1275, 1449, 1665, 1700, 1924, 1925, 1952, 1988, 2204, 2324, 2331, 2540, 2655, 2960, 2975, 3068, 3195, 3267, 3324, 3339, 3380, 3549, 3555, 3626, 3717, 4004, 4059, 4164, 4220, 4235, 4256, 4556, 4563, 4598, 4599, 4635, 4655, 4675, 4719

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

735 is a term since 735 and 736 are both nobly abundant numbers: A000005(735) = A000005(736) = 12, A000203(735) = 1368 and A000203(736) = 1512 are all abundant numbers.

Mathematica

abQ[n_] := DivisorSigma[1, n] > 2*n; nobAbQ[n_] := And @@ abQ /@ DivisorSigma[{0, 1}, n]; Select[Range[50000], nobAbQ[#] && nobAbQ[# + 1] &]

Crossrefs

Cf. A000005, A000203, A005101, A096399.

Subsequence of A349758.

Sequence in context: A025356 A025348 A126556 * A174456 A306474 A250053

Adjacent sequences: A349867 A349868 A349869 * A349871 A349872 A349873

Keyword

nonn

Author

Amiram Eldar, Dec 03 2021

Status

approved