A100990 - OEIS

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A100990

a(n) = n^21 mod 100.

0, 1, 52, 3, 4, 25, 56, 7, 8, 9, 0, 11, 12, 13, 64, 75, 16, 17, 68, 19, 0, 21, 72, 23, 24, 25, 76, 27, 28, 29, 0, 31, 32, 33, 84, 75, 36, 37, 88, 39, 0, 41, 92, 43, 44, 25, 96, 47, 48, 49, 0, 51, 52, 53, 4, 75, 56, 57, 8, 59, 0, 61, 12, 63, 64, 25, 16, 67, 68, 69, 0, 71, 72, 73, 24

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OFFSET

0,3

COMMENTS

Also n^(20k+1) mod 100 for any positive integer k.

There are 63 numbers (A075821) where the final two digits of n^21, n^41, n^61, etc. are equal to n.

Period 100.

LINKS

Jianing Song, Table of n, a(n) for n = 0..99 (a period)

FORMULA

a(n) = A051126(A010809(n), 100) = a(n-100).

EXAMPLE