A192775 The numbers n^2 as n runs through the numbers which are palindromes in base 2.

0, 1, 9, 25, 49, 81, 225, 289, 441, 729, 961, 1089, 2025, 2601, 3969, 4225, 5329, 7225, 8649, 9801, 11449, 14161, 16129, 16641, 23409, 27225, 35721, 38025, 47961, 53361, 65025, 66049, 74529, 88209, 97969, 105625, 116281, 133225, 145161, 149769, 162409, 182329, 196249, 207025, 221841, 245025, 261121, 263169, 314721, 342225, 400689, 416025, 480249, 514089, 585225

Offset

1,3

Links

Table of n, a(n) for n=1..55.

Prog

(Python)
def A192775(n):
    if n == 1: return 0
    a = 1<<(l:=n.bit_length()-2)
    m = a|(n&a-1)
    return ((m<<l+1)+int(bin(m)[-1:1:-1]or'0', 2) if a&n else (m<<l)+int(bin(m)[-2:1:-1]or'0', 2))**2 # Chai Wah Wu, Jul 23 2024

Crossrefs

Cf. A006995, A057148. See A192776 for these numbers written in base 2.

Sequence in context: A259417 A030156 A331587 * A318737 A246331 A141768

Adjacent sequences: A192772 A192773 A192774 * A192776 A192777 A192778

Keyword

nonn,base

Author

N. J. A. Sloane, Jul 09 2011

Status

approved