|
|
A064992
|
|
a(n) = usigma(n+1) - usigma(n), where usigma(n) is the sum of unitary divisors of n (A034448).
|
|
2
|
|
|
2, 1, 1, 1, 6, -4, 1, 1, 8, -6, 8, -6, 10, 0, -7, 1, 12, -10, 10, 2, 4, -12, 12, -10, 16, -14, 12, -10, 42, -40, 1, 15, 6, -6, 2, -12, 22, -4, -2, -12, 54, -52, 16, 0, 12, -24, 20, -18, 28, -6, -2, -16, 30, -12, 0, 8, 10, -30, 60, -58, 34, -16, -15, 19, 60, -76, 22, 6, 48, -72, 18, -16, 40
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
|
|
PROG
|
(PARI) usigma(n)= { local(f, s=1); f=factor(n); for(i=1, matsize(f)[1], s*=1 + f[i, 1]^f[i, 2]); return(s) } { u=1; for (n=1, 1000, u1=usigma(n + 1); a=u1 - u; u=u1; write("b064992.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 02 2009
|
|
CROSSREFS
|
|
|
KEYWORD
|
sign
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|