login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Row 8 of array in A059897.
3

%I #16 Apr 23 2019 09:17:36

%S 8,4,24,2,40,12,56,1,72,20,88,6,104,28,120,128,136,36,152,10,168,44,

%T 184,3,200,52,216,14,232,60,248,64,264,68,280,18,296,76,312,5,328,84,

%U 344,22,360,92,376,384,392,100,408,26,424,108,440,7,456,116,472,30,488,124,504,32

%N Row 8 of array in A059897.

%C Also column 8 of A059897.

%C A self-inverse permutation of the positive integers with no fixed points; A073675 composed with A120230.

%C The permutation swaps pairs of integers whose ratio is 1:8 or 1:2, these ratios corresponding to the factorizations 1*8 = 2*4 = 8.

%H Peter Munn, <a href="/A307266/b307266.txt">Table of n, a(n) for n = 1..5120</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%F a(n) = A059897(8,n) = A059897(n,8).

%F a(n) = A073675(A120230(n)) = A120230(A073675(n)) = A073675(n) * A120230(n) / n.

%o (PARI) T(n, k) = {if (n==1, return (k)); if (k==1, return (n)); my(fn=factor(n), fk=factor(k)); vp = setunion(fn[, 1]~, fk[, 1]~); prod(i=1, #vp, vp[i]^(bitxor(valuation(n, vp[i]), valuation(k, vp[i])))); }

%o a(n) = T(n, 8); \\ _Michel Marcus_, Apr 23 2019

%Y Cf. A059897, A073675, A120230, A307267.

%K nonn

%O 1,1

%A _Peter Munn_, Apr 01 2019