A332573 Numbers k such that k and k + 1 are both norm-deficient in Gaussian integers (A332572).

7, 16, 127, 128, 151, 248, 256, 343, 472, 536, 568, 631, 632, 751, 752, 823, 856, 943, 1048, 1111, 1136, 1207, 1303, 1327, 1328, 1336, 1432, 1527, 1528, 1591, 1687, 1688, 1711, 1712, 1783, 1816, 1912, 2031, 2032, 2047, 2048, 2103, 2167, 2263, 2416, 2487, 2488

Offset

1,1

Links

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

Example

7 is a term since both 7 and 7 + 1 = 8 are norm-deficient in Gaussian integers (A332572).

Mathematica

normDefQ[z_] := Abs[DivisorSigma[1, z, GaussianIntegers -> True]]^2 < 2*Abs[z]^2; Select[Range[2500], normDefQ[#] && normDefQ[# + 1] &]

Crossrefs

Cf. A005100, A103228, A103229, A103230, A317047, A332572.

Sequence in context: A029498 A351531 A181777 * A129422 A184062 A101122

Adjacent sequences: A332570 A332571 A332572 * A332574 A332575 A332576

Keyword

nonn

Author

Amiram Eldar, Feb 16 2020

Status

approved