A332574 Numbers k such that k, k + 1 and k + 2 are all norm-deficient in Gaussian integers (A332572).

127, 631, 751, 1327, 1527, 1687, 1711, 2031, 2047, 2487, 2647, 3207, 3271, 3351, 3511, 3831, 4567, 4791, 4911, 5127, 6007, 6087, 6711, 7431, 8247, 8367, 8391, 8407, 8551, 8751, 8871, 9031, 9447, 9991, 10407, 10551, 10887, 10927, 11631, 12471, 12567, 12631, 13807

Offset

1,1

Links

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

Example

127 is a term since 127, 128 and 129 are all norm-deficient in Gaussian integers (A332572).

Mathematica

normDefQ[z_] := Abs[DivisorSigma[1, z, GaussianIntegers -> True]]^2 < 2*Abs[z]^2; Select[Range[10^4], AllTrue[# + Range[0, 2], normDefQ] &]

Crossrefs

Cf. A005100, A103228, A103229, A103230, A317047, A332572, A332573.

Sequence in context: A152783 A299890 A200813 * A049202 A204737 A060201

Adjacent sequences: A332571 A332572 A332573 * A332575 A332576 A332577

Keyword

nonn

Author

Amiram Eldar, Feb 16 2020

Status

approved