A351533 Odd numbers k that are multiples of 3 and for which sigma(k) is congruent to 2 modulo 4.

45, 117, 153, 261, 333, 369, 405, 477, 549, 657, 801, 873, 909, 981, 1017, 1053, 1233, 1341, 1377, 1413, 1557, 1629, 1737, 1773, 2061, 2097, 2169, 2205, 2313, 2349, 2421, 2493, 2529, 2637, 2817, 2853, 2925, 2997, 3033, 3141, 3177, 3321, 3357, 3501, 3573, 3609, 3645, 3681, 3789, 3825, 3897, 4041, 4113, 4149, 4293

Offset: 1

Author

Antti Karttunen, Feb 13 2022

Keywords

• nonn

Links

• Index entries for sequences related to sigma(n)

Crossrefs

Intersection of A008585 and A191218. Complement of A351535 in A191218.

Cf. A351534 (subsequence).

Programs

Mathematica

Select[3*Range[1, 1400, 2], Mod[DivisorSigma[1, #], 4] == 2 &] (* Amiram Eldar, Feb 13 2022 *)

PARI

isA351533(n) = ((n%2) && !(n%3) && (2 == (sigma(n)%4)));