OFFSET
1,6
COMMENTS
LINKS
Georg Fischer, Table of n, a(n) for n = 1..80 [first 78 terms from B. D. Swan]
FORMULA
EXAMPLE
a(8)=8 because Fibonacci(8)=21, the proper divisors of 21 are 1,3 and 7; consequently, a(8) = 1 + 3 + 7 - 3 = 8. - Emeric Deutsch, Jan 02 2009
MAPLE
with(combinat): with(numtheory): seq(sigma(fibonacci(n))-fibonacci(n)-tau(fibonacci(n))+1, n = 1 .. 45); # Emeric Deutsch, Jan 02 2009
PROG
(Magma) [DivisorSigma(1, f)-f-DivisorSigma(0, f)+1 where f is Fibonacci(n):n in [1..43] ]; // Marius A. Burtea, Feb 18 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Dec 20 2008
EXTENSIONS
Extended by Emeric Deutsch, Jan 02 2009
a(79)-a(80) in b-file corrected by Georg Fischer, Feb 18 2020
STATUS
approved