A319992 a(n) = Product_{d|n, d<n} A019565(d)^[2 == d mod 3].

1, 1, 1, 3, 1, 3, 1, 3, 1, 30, 1, 3, 1, 3, 10, 21, 1, 3, 1, 30, 1, 126, 1, 21, 10, 3, 1, 315, 1, 30, 1, 21, 42, 66, 10, 3, 1, 3, 1, 11550, 1, 315, 1, 126, 10, 990, 1, 21, 1, 30, 22, 693, 1, 3, 420, 2205, 1, 2310, 1, 1650, 1, 3, 1, 273, 10, 126, 1, 66, 330, 245700, 1, 21, 1, 3, 10, 585, 42, 693, 1, 11550, 1, 546, 1, 315, 220, 3, 770

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..8192

Formula

a(n) = Product_{d|n, d<n} A019565(d)^[2 == d mod 3].

a(n) = A293214(n) / (A319990(n)*A319991(n)).

For all n >= 1:

A007814(a(n)) = A320005(n).

A048675(a(n)) = A293898(n).

A195017(a(n)) = -A293896(n) mod 3.

Prog

(PARI)
A019565(n) = {my(j, v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ From A019565
A319992(n) = { my(m=1); fordiv(n, d, if((d<n)&&(2==(d%3)), m *= A019565(d))); m; };

Crossrefs

Cf. A019565, A293214, A293896, A293898, A319990, A319991, A320005, A320012 (rgs-transform).

Cf. also A293222.

Sequence in context: A319137 A074122 A335182 * A255894 A135023 A367805

Adjacent sequences: A319989 A319990 A319991 * A319993 A319994 A319995

Keyword

nonn

Author

Antti Karttunen, Oct 03 2018

Status

approved