prog.sf

#!/usr/bin/ruby

# a(n) is the maximum prime factor of the concatenation of a(n-2) and a(n-1), with a(1)=1 and a(2)=2
# https://oeis.org/A280894

include('../../../factordb/auto.sf')

func a(n) is cached {
    return 1 if (n == 1)
    return 2 if (n == 2)
    gpf(Num(join('', a(n-2), a(n-1))))
}

var fh = File('bfile.txt').open_w

fh.autoflush(true)

for n in (1..10000) {
    var row = "#{n} #{a(n)}"
    say row
    fh.say(row)
}

__END__

not FF: 6520842354140118040355763693879924323002857350048725428113176051404264796719454440763187888611339210218453742791930047642196926300803432024917606770110282689443102347792520396533935876342678176379567979056549996383541341367