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A214617
Primes written in the factorial base.
2
10, 11, 21, 101, 121, 201, 221, 301, 321, 1021, 1101, 1201, 1221, 1301, 1321, 2021, 2121, 2201, 2301, 2321, 3001, 3101, 3121, 3221, 4001, 4021, 4101, 4121, 4201, 4221, 10101, 10121, 10221, 10301, 11021, 11101, 11201, 11301, 11321, 12021, 12121, 12201, 12321
OFFSET
1,1
COMMENTS
The factorial base system uses 1!, 2!, 3!, ..., n! instead of powers of b, b^0, b^1, b^2, ... for some base b.
To be consistent with the normal base 10 system, the largest factorial used appears on the left.
LINKS
FORMULA
a(n) = A007623(A000040(n)).
EXAMPLE
prime(6) = 13 = 2*3! + 1! so a(6) = 201.
MAPLE
b:= proc(n, i) local r; `if`(n<i, n,
10*b(iquo(n, i, 'r'), i+1)+ r)
end:
a:= n-> b(ithprime(n), 2):
seq(a(n), n=1..50); # Alois P. Heinz, Mar 16 2013
CROSSREFS
Sequence in context: A041204 A041202 A324550 * A041200 A041847 A113702
KEYWORD
nonn,base
AUTHOR
Jon Perry, Mar 06 2013
STATUS
approved