

A173956


nth primorial modulo n.


1



0, 0, 0, 2, 0, 0, 0, 2, 6, 0, 0, 6, 0, 0, 0, 10, 0, 12, 0, 10, 0, 0, 0, 6, 20, 0, 3, 14, 0, 0, 0, 22, 0, 0, 0, 6, 0, 0, 0, 30, 0, 0, 0, 22, 30, 0, 0, 18, 21, 40, 0, 26, 0, 30, 0, 42, 0, 0, 0, 30, 0, 0, 42, 18, 0, 0, 0, 34, 0, 0, 0, 30, 0, 0, 60, 38, 0, 0, 0, 50, 12, 0, 0, 42, 0, 0, 0, 66, 0, 30, 0
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OFFSET

1,4


COMMENTS

Very similar to A076998.
For all n, a(A013929(n)) != 0, and a(A005117(n)) = 0.  Michel Marcus, Sep 03 2013 and Antti Karttunen, Nov 20 2017


LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384


FORMULA

a(n) = A002110(n) mod n.  Michel Marcus, Sep 03 2013


EXAMPLE

a(9) = p(9)# mod 9 = 23# mod 9 = 2*3*5*7*11*13*17*19*23 mod 9 = 6.


MATHEMATICA

Array[Mod[Product[Prime@ i, {i, #}], #] &, 91] (* Michael De Vlieger, Nov 20 2017 *)


PROG

(PARI) a(n) = prod(i=1, n, prime(i)) % n; \\ Michel Marcus, Sep 03 2013


CROSSREFS

Cf. A002110, A005117 (the positions of zeros).
Differs from A076998 for the first time at n=16, where a(16) = 10, while A076998(16) = 2.
Sequence in context: A320437 A059286 A076998 * A306078 A284273 A083927
Adjacent sequences: A173953 A173954 A173955 * A173957 A173958 A173959


KEYWORD

easy,nonn


AUTHOR

Carl R. White, Mar 03 2010


STATUS

approved



