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A143263
A positive integer n is included if the binary representation of the number of divisors of n occurs in the binary representation of n at least once.
3
1, 2, 5, 8, 11, 12, 13, 17, 19, 23, 24, 25, 28, 29, 33, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 45, 47, 49, 50, 51, 52, 53, 56, 57, 59, 60, 61, 65, 66, 67, 69, 70, 71, 73, 74, 76, 77, 79, 80, 81, 82, 83, 88, 89, 92, 96, 97, 98, 99, 100, 101, 103, 104, 107, 108, 109, 113, 115
OFFSET
1,2
LINKS
EXAMPLE
37 has 2 divisors. 37 in binary is 100101. 2 in binary is 10. 10 occurs in two places in 100101: (10)0(10)1. So 37 occurs in this sequence.
MAPLE
filter:= proc(n) local L, t, Lt, m, mt;
L:= convert(n, base, 2);
m:= nops(L);
Lt:= convert(numtheory:-tau(n), base, 2);
mt:= nops(Lt);
ormap(i -> L[i..i+mt-1]=Lt, [$1..m-mt+1]);
end proc:
select(filter, [$1..1000]); # Robert Israel, Jun 17 2021
CROSSREFS
Sequence in context: A019995 A188802 A031141 * A327138 A102624 A070328
KEYWORD
base,nonn
AUTHOR
Leroy Quet, Aug 03 2008
EXTENSIONS
Extended by Ray Chandler, Nov 09 2008
STATUS
approved