A342040 Binary palindromes of odd length.

1, 101, 111, 10001, 10101, 11011, 11111, 1000001, 1001001, 1010101, 1011101, 1100011, 1101011, 1110111, 1111111, 100000001, 100010001, 100101001, 100111001, 101000101, 101010101, 101101101, 101111101, 110000011, 110010011, 110101011

Offset

1,2

Comments

Subsequence of A057148.

Links

Table of n, a(n) for n=1..26.

Formula

a(n) = A007088(A048700(n)).

Mathematica

a[1] = 1; a[n_] := FromDigits[Join[#, {Mod[n, 2]}, Reverse[#]] &@ IntegerDigits[Floor[n/2], 2]]; Array[a, 26] (* Amiram Eldar, Apr 28 2021 *)

Prog

(Python)
def A342040(n):
    s = bin(n)[2:]
    return int(s+s[-2::-1]) # Chai Wah Wu, Feb 26 2021

Crossrefs

Cf. A006995, A007088, A048700, A057148, A070939, A305989, A342036.

Sequence in context: A283590 A279173 A279873 * A290413 A288904 A289039

Adjacent sequences: A342037 A342038 A342039 * A342041 A342042 A342043

Keyword

nonn,base,easy

Author

Seiichi Manyama, Feb 26 2021

Status

approved