login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A175861
a(n) = characteristic function of numbers k such that A175856(m) = k has no solution for any m, where A175856(m): a(m) = m for m = noncomposites, a(m) = previous term - 1 for m = composites.
7
0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0
OFFSET
1,1
COMMENTS
a(n) = characteristic function of numbers from A175859(n). a(n) = 1 if A175856(m) not equal to n for any m, else 0. a(n) = 1 for such n that A175862(n) = 0. a(n) = 0 for such n that A175862(n) >= 1. a(n) + A175860(n) = A000012(n).
FORMULA
a(n) = 1 - A175860(n).
PROG
(PARI) A175861(n) = (1-A175860(n)); \\ Uses program from A175860. - Antti Karttunen, Nov 08 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Sep 29 2010
STATUS
approved