A318466 a(n) = 2*n OR A000203(n), where OR is bitwise-or (A003986) and A000203 = sum of divisors.

3, 7, 6, 15, 14, 12, 14, 31, 31, 22, 30, 28, 30, 28, 30, 63, 50, 39, 54, 42, 42, 44, 62, 60, 63, 62, 62, 56, 62, 124, 62, 127, 114, 118, 118, 91, 110, 124, 126, 90, 122, 116, 126, 92, 94, 92, 126, 124, 123, 125, 110, 106, 126, 124, 110, 120, 114, 126, 126, 248, 126, 124, 126, 255, 214, 148, 198, 254, 234, 156, 206

Offset: 1

Author

Antti Karttunen, Aug 26 2018

Keywords

• nonn
• look
• base

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Index entries for sequences related to binary expansion of n
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A003986, A224880, A318467, A318468.

Cf. also A318456.

Programs

Mathematica

Array[BitOr[2 #, DivisorSigma[1, #]] &, 71] (* Michael De Vlieger, Mar 30 2019 *)

PARI

A318466(n) = bitor(2*n,sigma(n));

Python

from sympy import divisor_sigma
def A318466(n): return (n<<1)|int(divisor_sigma(n)) # Chai Wah Wu, Jul 10 2022

Formula

a(n) = A003986(2*n, A000203(n)).

a(n) = A224880(n) - A318468(n).