A367547 - OEIS

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A367547

Euclid's triangle A217831 represented as binary numbers.

0, 11, 10, 110, 1010, 11110, 100010, 1111110, 10101010, 110110110, 1010001010, 11111111110, 100010100010, 1111111111110, 10101000101010, 110100110010110, 1010101010101010, 11111111111111110, 100010100010100010, 1111111111111111110, 10100010101010001010, 110110010110100110110

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

OFFSET

0,2

COMMENTS

The sequence represents the rows of Euclid's triangle A217831 as unsigned binary integers. If a '0' is prepended to the most significant bit (for n > 1) the terms can also be seen as palindromic binary strings. The decimal representation of the sequence is A367544.

LINKS

Table of n, a(n) for n=0..21.

MATHEMATICA

A367547[n_]:=FromDigits[Boole[CoprimeQ[n, Range[0, n]]]];

Array[A367547, 30, 0] (* Paolo Xausa, Nov 24 2023 *)

PROG

(SageMath) # For Python include 'import math' for math.gcd.

def A367547(n):

cop = [int(gcd(i, n) == 1) for i in range(n + 1)]

return int(''.join(map(str, cop)))

print([A367547(n) for n in range(22)])

(PARI) a(n) = fromdigits(vector(n+1, i, gcd(i-1, n)==1), 10); \\ Michel Marcus, Nov 24 2023