A192775 - OEIS

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

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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