OFFSET
2,1
COMMENTS
If n-1 is in A103746, then a(n) = (prime(n)*prime(n-1)+3)/2. - Robert Israel, Jun 03 2020
LINKS
Robert Israel, Table of n, a(n) for n = 2..10000
FORMULA
MAPLE
p:= 2: R:= NULL:
for n from 2 to 50 do
q:= p; p:= nextprime(p);
R:= R, convert(numtheory:-factorset(p*q-1), `+`)
od:
R; # Robert Israel, Jun 03 2020
PROG
(PARI) sopf(n) = my(fac=factor(n)); sum(i=1, matsize(fac)[1], fac[i, 1]) ;
a(n) = sopf(prime(n)*prime(n-1) - 1); \\ Michel Marcus, Sep 30 2013
CROSSREFS
KEYWORD
nonn,look
AUTHOR
EXTENSIONS
Offset set to 2 and a(1) removed by Michel Marcus, Sep 30 2013
STATUS
approved