OFFSET
1,1
COMMENTS
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
87 is in the sequence because 87 = 3 * 29 is semiprime, "eighty-seven" has 4 syllables, and 4 = 2^2 is also semiprime.
106 is in the sequence because 106 = 2 * 53 is semiprime and "one hundred six" has semiprime 4 syllables.
111 is in the sequence because 111 = 3 * 37 is semiprime and "one hundred eleven" has semiprime 6 = 2*3 syllables.
PROG
(Python) # uses function in A075774
from sympy import factorint
def issemiprime(n): return sum(factorint(n).values()) == 2
def ok(n): return issemiprime(A075774(n)) and issemiprime(n)
print([k for k in range(310) if ok(k)]) # Michael S. Branicky, May 27 2024
CROSSREFS
KEYWORD
nonn,word,easy
AUTHOR
Jonathan Vos Post, Nov 04 2013
EXTENSIONS
Corrected and extended by Charles R Greathouse IV, Jan 23 2014
STATUS
approved