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A233416
c-perfect numbers.
3
11, 71, 226, 3676, 16911, 1143267, 4721203, 8906035
OFFSET
1,1
COMMENTS
A number k is called a c-perfect number if the sum of its proper c-divisors equals k.
For the definition of a c-divisor of an integer, see comment in A124771.
From Charlie Neder, Jan 17 2019: (Start)
Sequence in binary: 1011, 1000111, 11100010, 111001011100, 100001000001111, 100010111000111100011, 10010000000101000110011, 100001111110010100110011...
Next term > 10^7. (End)
FORMULA
A233394(a(n))=2*a(n).
EXAMPLE
For n=11 which is a concatenation of binary parts (10)(1)(1); we have proper positive c-divisors 1, 2, 3, and 5, the sum of which is 11, so 11 is in the sequence.
CROSSREFS
Sequence in context: A333408 A174202 A139850 * A174822 A201790 A268985
KEYWORD
nonn,more,base
AUTHOR
EXTENSIONS
a(6)-a(8) from Charlie Neder, Jan 17 2019
STATUS
approved