OFFSET
1,1
COMMENTS
No more terms <= 200.
k=7634 is a term, but it is not known to be the next term after 78. - Jeppe Stig Nielsen, May 12 2023
LINKS
Hisanori Mishima, Euler numbers (n = 0 to 78).
Hisanori Mishima, Euler numbers (n = 80 to 106).
Prime Pages, -E(7634)/1559.
Sam Wagstaff, Factorization of Bernoulli and Euler numbers.
EXAMPLE
a(2) = 10 so Euler(10) = 50521 = 19 * 2659 is a semiprime.
PROG
(PARI) is(k) = k%2==0 && bigomega(eulerfrac(k))==2 \\ slow, from Jeppe Stig Nielsen, May 12 2023
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Eric Chen, Dec 24 2014
STATUS
approved