Sloane shows 42042 for k=11, rather than my 7871, so something went wrong. Apparently UBASIC returns a zero for the prmdiv function if its largest prime divisor is bigger than a certain value, such as in:
?prmdiv(98765432137) 0
C'est l'informatique.
blackjack
<a href="http://c.casalemedia.com/c?s=51816&f=3&id=0" target="_blank"><img src="http://as.casalemedia.com/s?s=51816&u=http://perplexus.info&f=3&id=0&if=0" width="120" height="600" border="0"></a>
flooble's webmaster puzzle
re: computer solution--something bad happened at the unasked-for k=11
