OFFSET
1,2
COMMENTS
This sequence is a variant of A285487. Both sequences are permutations of the natural numbers and have similar graphical features.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
OEIS Wiki, "Fermi-Dirac representation" of n
Rémy Sigrist, Colored scatterplot of the first 10000 terms (where the color is function of A064547(a(n)))
Rémy Sigrist, PARI program for A306854
FORMULA
A064547(a(n) * a(n+1)) >= 5.
EXAMPLE
The first terms, alongside the Fermi-Dirac factorization of a(n) * a(n+1), are:
n a(n) a(n) * a(n+1)
-- ---- -------------
1 1 2^(2^0) * 2^(2^1) * 3^(2^0) * 5^(2^0) * 7^(2^0)
2 840 2^(2^0) * 2^(2^1) * 3^(2^1) * 5^(2^0) * 7^(2^0)
3 3 2^(2^0) * 2^(2^1) * 3^(2^0) * 5^(2^0) * 7^(2^0)
4 280 2^(2^0) * 2^(2^1) * 3^(2^1) * 5^(2^0) * 7^(2^0)
5 9 2^(2^0) * 2^(2^1) * 3^(2^0) * 3^(2^1) * 5^(2^0)
6 120 2^(2^0) * 2^(2^1) * 3^(2^0) * 5^(2^0) * 7^(2^0)
7 7 2^(2^0) * 2^(2^1) * 3^(2^0) * 3^(2^1) * 7^(2^0)
8 216 2^(2^0) * 2^(2^1) * 3^(2^0) * 3^(2^1) * 5^(2^0)
9 5 2^(2^0) * 2^(2^1) * 3^(2^0) * 5^(2^0) * 7^(2^0)
10 168 2^(2^0) * 2^(2^1) * 3^(2^0) * 7^(2^0) * 11^(2^0)
11 11 2^(2^0) * 3^(2^0) * 5^(2^0) * 7^(2^0) * 11^(2^0)
12 210 2^(2^0) * 2^(2^1) * 3^(2^0) * 5^(2^0) * 7^(2^0)
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Rémy Sigrist, Mar 13 2019
STATUS
approved