

A215747


a(n) = (2)^n mod n.


3



0, 0, 1, 0, 3, 4, 5, 0, 1, 4, 9, 4, 11, 4, 7, 0, 15, 10, 17, 16, 13, 4, 21, 16, 18, 4, 1, 16, 27, 4, 29, 0, 25, 4, 17, 28, 35, 4, 31, 16, 39, 22, 41, 16, 28, 4, 45, 16, 19, 24, 43, 16, 51, 28, 12, 32, 49, 4, 57, 16, 59, 4, 55, 0, 33, 64, 65, 16, 61, 44, 69, 64, 71, 4, 7
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OFFSET

1,5


COMMENTS

n^(n+2) mod (n+2) is essentially the same.
Indices of 0's: 2^k  1, k>=0.
Indices of 1's: A006521 except the first term.
Indices of 3's: A015940.
Indices of 5's: 7, 133, 1517, 11761, ...
a(A000040(n)) = A000040(n)2 = A040976(n).


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000


EXAMPLE

a(5) = (2)^5 mod 5 = 32 mod 5 = 3.


MAPLE

a:= n> (2)&^n mod n:
seq(a(n), n=1..100); # Alois P. Heinz, Apr 08 2015


PROG

(Python)
for n in range(1, 333):
print((2)**n % n, end=', ')


CROSSREFS

Cf. A015910, A082493, A082494, A110146, A213381.
Sequence in context: A100649 A158962 A263824 * A246667 A199066 A306584
Adjacent sequences: A215744 A215745 A215746 * A215748 A215749 A215750


KEYWORD

nonn,look


AUTHOR

Alex Ratushnyak, Aug 23 2012


STATUS

approved



