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A233416 c-perfect numbers. 3
11, 71, 226, 3676, 16911, 1143267, 4721203, 8906035 (list; graph; refs; listen; history; text; internal format)
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)

LINKS

Table of n, a(n) for n=1..8.

Index entries for sequences related to binary expansion of n

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

Cf. A124771, A233394.

Sequence in context: A089720 A174202 A139850 * A174822 A201790 A268985

Adjacent sequences:  A233413 A233414 A233415 * A233417 A233418 A233419

KEYWORD

nonn,more,base

AUTHOR

Vladimir Shevelev and Peter J. C. Moses, Dec 09 2013

EXTENSIONS

a(6)-a(8) from Charlie Neder, Jan 17 2019

STATUS

approved

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Last modified February 19 00:35 EST 2020. Contains 332028 sequences. (Running on oeis4.)