Cubic Recurring Digital Invariant/Examples/919

Example of Cubic Recurring Digital Invariant

$919$ is a cubic recurring digital invariant:

\(\ds 919: \ \ \)

\(\ds 9^3 + 1^3 + 9^3\)

\(=\)

\(\ds 729 + 1 + 729\)

\(\ds = 1459\)

\(\ds 1459: \ \ \)

\(\ds 1^3 + 4^3 + 5^3 + 9^3\)

\(=\)

\(\ds 1 + 64 + 125 + 729\)

\(\ds = 919\)

$\blacksquare$

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $153$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $153$