A303778 Divisor-or-multiple permutation of squarefree numbers: a(n) = A019565(A303775(n)).

1, 2, 6, 3, 15, 5, 10, 30, 210, 105, 35, 7, 70, 14, 42, 21, 1155, 11, 22, 66, 33, 330, 55, 110, 2310, 165, 2145, 429, 143, 13, 858, 286, 26, 4290, 1430, 715, 65, 5005, 385, 77, 770, 154, 462, 231, 30030, 10010, 2002, 1001, 91, 15015, 3003, 39, 6006, 78, 390, 195, 1365, 455, 910, 130, 2730, 182, 546, 273, 4641, 17, 1870, 935, 187, 2805, 561, 51, 5610, 374, 34

Offset: 0

Author

Antti Karttunen, May 06 2018

Keywords

• nonn

Comments

Each a(n+1) is either a divisor or a multiple of a(n).

Links

• Antti Karttunen, Table of n, a(n) for n = 0..16383

Crossrefs

Cf. A005117, A019565, A303775.

Cf. also A304087.

Programs

PARI

A019565(n) = {my(j,v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ From A019565
A303778(n) = A019565(A303775(n)); \\ Needs also code from A303775.

Formula

a(n) = A019565(A303775(n)).