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

Author

Amiram Eldar, Dec 03 2021

Keywords

• nonn

Examples

			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.
		

Links

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

Crossrefs

Cf. A000005, A000203, A005101, A096399.

Subsequence of A349758.

Programs

Mathematica

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