# About Self Number, which is found by D. R. Kaprekar.

I'm trying to understand the algorithm to find self-number.
But I don't know what does C, k, j, b is mean at this formula. What's that? How do I understand and what should I assign to solve them?

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$C_k$ refers to the $k^{th}$ generated self number ($C_1$ is the first, $C_2$ is the second, ..etc.). Let's use the first formula to generate some self-numbers:
$C_1 = 9$ (as written between brackets)
We get $C_2$ by replacing $k$ in the formula by 2. $C_2 = 8*10^{2-1} + C_{2-1} + 8 = 8*10 + C_1 + 8 = 8*10 + 9 + 8 = 97$ (by substituting $C_1 = 9$).