OFFSET
5,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 5..10000
FORMULA
EXAMPLE
For n < 5, there is no odd abundant number equal to the product of n distinct primes.
For 5 <= n <= 8, the largest odd abundant number equal to the product of n consecutive primes is 3*...*a(n) with a(n) = prime(n+1).
For 9 <= n <= 17, the largest odd abundant number equal to the product of n consecutive primes is 5*...*a(n) with a(n) = prime(n+2).
For 18 <= n <= 30, the largest odd abundant number equal to the product of n consecutive primes is 7*...*a(n) with a(n) = prime(n+3).
For 31 <= n <= 45, the largest odd abundant number equal to the product of n consecutive primes is 11*...*a(n) with a(n) = prime(n+4).
For 46 <= n <= 66, the largest odd abundant number equal to the product of n consecutive primes is 13*...*a(n) with a(n) = prime(n+5).
PROG
(PARI) a(r, f=vector(r, i, prime(i+1)), o)={ while(sigma(factorback(f), -1)>2, o=f; f=concat(f[^1], nextprime(f[r]+1))); o[#o]} \\ Intentionally throws an error when n < 5.
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, May 01 2017
EXTENSIONS
a(66) corrected by Amiram Eldar, Sep 24 2019
STATUS
approved