A050424 - OEIS

A050424

Numbers for which in base 2 the least number of digits that can be removed to leave a palindrome (possibly beginning with 0) is 5.

880, 936, 944, 964, 968, 976, 992, 1504, 1744, 1760, 1776, 1840, 1872, 1888, 1924, 1936, 1944, 1952, 1956, 1960, 1968, 1984, 1986, 1988, 1992, 2000, 2016, 2110, 2111, 2142, 2143, 2158, 2159, 2166, 2167, 2206, 2207, 2222, 2223, 2334, 2335, 2784, 2896, 2912

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..44.

PROG

(Python)

from itertools import combinations

def ok(n):

b = bin(n)[2:]

for digs_to_remove in range(6):

for skip in combinations(range(len(b)), digs_to_remove):

newb = "".join(b[i] for i in range(len(b)) if i not in skip)

if newb == newb[::-1]: return (digs_to_remove == 5)

return False

print(list(filter(ok, range(2913)))) # Michael S. Branicky, Aug 15 2021

CROSSREFS

Sequence in context: A063051 A190030 A118799 * A206341 A357495 A024393

Adjacent sequences: A050421 A050422 A050423 * A050425 A050426 A050427

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

EXTENSIONS

Data corrected by Sean A. Irvine, Aug 15 2021

STATUS

approved