Even Perfect Number is Triangular/Proof 2

Theorem

All perfect numbers which are even are triangular.

Proof

Follows from:

Even Perfect Number is Hexagonal

Hexagonal Number is Triangular Number

$\blacksquare$

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $45$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $45$