Talk:Descartes number

Negative primes

Either the definition needs a modification, or there is another Descartes number. If we pretend that -127 is a positive prime, i.e., $\sigma (-127)=-126$, then

$\sigma (3^{4}7^{2}11^{2}19^{2}(-127))=\sigma (3^{4})\sigma (7^{2})\sigma (11^{2})\sigma (19^{2})\sigma (-127)=(11^{2})\cdot (3\cdot 19)\cdot (7\cdot 19)\cdot (3\cdot 127)\cdot (-2\cdot 3^{2}\cdot 7)=2\cdot 3^{4}7^{2}11^{2}19^{2}(-127).$ — Preceding unsigned comment added by 84.55.98.173 (talk) 07:27, 27 January 2016 (UTC)