

A175192


a(n) = characteristic function of numbers k such that A000203(m) = k has solution, where A000203(m) = sums of divisors of m.


7



1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0
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OFFSET

1,1


COMMENTS

a(n) = 1 if A000203(m) = n for some m, else 0.
a(n) = 1 for n such that A054973(n) >= 1. a(n) = 0 for n such that A054973(n) = 0.


LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537
Index entries for characteristic functions


MATHEMATICA

nn = 200; t = Union[Select[DivisorSigma[1, Range[nn]], # <= nn &]]; t2 = Table[0, {200}]; t2[[t]] = 1; t2 (* T. D. Noe, Jan 24 2012 *)


PROG

(PARI)
up_to = 65537
v175192 = vector(up_to);
for(k=1, up_to, t=sigma(k); if(t<=up_to, v175192[t] = 1)); \\ See also code in A054973.
write_to_bfile(start_offset, vec, bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)1, " ", vec[n])); }
write_to_bfile(1, v175192, "b175192_upto65537.txt");
\\ Antti Karttunen, Oct 20 2017


CROSSREFS

Characteristic function of A002191.
Cf. A000203, A054973.
Sequence in context: A260192 A057078 A127245 * A088150 A117567 A307183
Adjacent sequences: A175189 A175190 A175191 * A175193 A175194 A175195


KEYWORD

nonn


AUTHOR

Jaroslav Krizek, Mar 01 2010


EXTENSIONS

More terms from Antti Karttunen, Oct 20 2017


STATUS

approved



