A260421 - OEIS

A260421

a(1) = 1, a(A206074(n)) = 1 + (2*a(n)), a(A205783(1+n)) = 2*a(n), where A206074 and A205783 give binary codes for polynomials with coefficients 0 or 1 that are irreducible [resp. reducible] over Q.

1, 3, 7, 2, 15, 6, 5, 14, 4, 30, 31, 12, 13, 10, 28, 8, 11, 60, 29, 62, 24, 26, 9, 20, 61, 56, 16, 22, 63, 120, 25, 58, 124, 48, 52, 18, 27, 40, 122, 112, 21, 32, 57, 44, 126, 240, 17, 50, 116, 248, 96, 104, 23, 36, 121, 54, 80, 244, 59, 224, 125, 42, 64, 114, 88, 252, 49, 480, 53, 34, 19, 100, 41, 232, 496, 192, 123, 208, 113, 46, 33, 72, 45

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

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

Index entries for sequences that are permutations of the natural numbers

FORMULA

If A257000(n) = 1 [when n is one of the terms of A206074] then a(n) = 1 + 2*a(A255574(n)), otherwise a(n) = 2*A260421(A255572(n)).

As a composition of related permutations:

a(n) = A246377(A260424(n)).

a(n) = A246201(A260426(n)).

PROG