OFFSET
1,3
COMMENTS
a(n) is the sum of the quotients in integer division of prime(n) by all smaller primes.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
Lorenzo Sauras-Altuzarra, Some properties of the factors of Fermat numbers, Art Discrete Appl. Math. (2022).
FORMULA
a(n) = A308495(n) - 2. - Hugo Pfoertner, Mar 04 2021
EXAMPLE
a(4) = floor(7/2) + floor(7/3) + floor(7/5) = 6.
MAPLE
f:= proc(n) local t, i, s;
t:= ithprime(n);
add(floor(t/ ithprime(i)), i=1..n-1)
end proc:
map(f, [$1..100]);
MATHEMATICA
Table[Sum[Floor[Prime[n]/Prime[j]], {j, n-1}], {n, 64}] (* Stefano Spezia, Mar 04 2021 *)
PROG
(PARI) a(n) = sum(j=1, n-1, prime(n)\prime(j)); \\ Michel Marcus, Mar 04 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Mar 03 2021
STATUS
approved