OFFSET
1,1
COMMENTS
If a(n) = 0 then n is a Ruth-Aaron number. - Andrew Slattery, Apr 15 2020
FORMULA
a(n) = sopfr(n) - sopfr(n+1), where sopfr = A001414. - Wesley Ivan Hurt, Aug 10 2016
EXAMPLE
a(24)=-1 because 24=2*2*2*3, 25=5*5 and (2+2+2+3)-(5+5)=-1.
CROSSREFS
KEYWORD
sign
AUTHOR
Charles K. Layman (cklayman(AT)juno.com), Nov 25 2003
STATUS
approved