A324727 Odd numbers such that 2n is equal to A318466(n), bitor(2*n,sigma(n)), where bitor is A003986.

3, 7, 15, 21, 31, 55, 57, 63, 93, 105, 111, 127, 171, 189, 201, 213, 215, 217, 231, 237, 249, 253, 255, 315, 351, 357, 363, 369, 381, 393, 447, 465, 469, 473, 483, 489, 497, 501, 511, 651, 705, 747, 759, 789, 813, 831, 833, 879, 889, 895, 917, 959, 987, 989, 1001, 1015, 1023, 1155, 1365, 1377, 1407, 1467, 1491, 1503, 1505, 1515, 1533, 1595

Offset: 1

Author

Antti Karttunen, Mar 15 2019

Keywords

• nonn
• look

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000
• Index entries for sequences related to binary expansion of n
• Index entries for sequences where any odd perfect numbers must occur
• Index entries for sequences related to sigma(n)

Crossrefs

Odd terms of A324726.

Cf. A000203, A003986, A318466, A324647, A324718, A324719.

Programs

Mathematica

Select[Range[1, 2000, 2], 2*# == BitOr[2*#, DivisorSigma[1, #]] &] (* Paolo Xausa, Mar 11 2024 *)

PARI

for(n=1,oo,if((n%2)&&((2*n)==bitor(2*n,sigma(n))),print1(n,", ")));