

A036434


Integers which cannot be written as k+tau(k) for some k.


2



1, 3, 6, 8, 11, 16, 17, 20, 22, 23, 27, 29, 35, 36, 40, 41, 44, 46, 47, 53, 54, 57, 60, 65, 67, 68, 70, 76, 77, 79, 80, 83, 87, 88, 92, 93, 94, 100, 101, 106, 107, 114, 116, 117, 121, 125, 128, 131, 132, 134, 135, 140, 142, 148, 155, 156, 157, 158, 161, 164, 166
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

Invented by the HR concept formation program.


LINKS

Table of n, a(n) for n=1..61.
S. Colton, Refactorable Numbers  A Machine Invention, J. Integer Sequences, Vol. 2, 1999, #2.
S. Colton, HR  Automatic Theory Formation in Pure Mathematics


EXAMPLE

None of 1,2,3,4,5,6,7 are such that k+tau(k)=8, so 8 is in the sequence.


PROG

(PARI) isok(n) = sum(k=1, n, k+numdiv(k) != n) == n; \\ Michel Marcus, Dec 08 2014


CROSSREFS

Cf. A036438.
Sequence in context: A164910 A276583 A135736 * A140400 A190430 A188018
Adjacent sequences: A036431 A036432 A036433 * A036435 A036436 A036437


KEYWORD

nonn


AUTHOR

Simon Colton (simonco(AT)cs.york.ac.uk)


STATUS

approved



