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A050429 Numbers for which in base 2 the least number of digits that can be removed to leave a base 2 palindromic number (beginning with 1) is 5. 4
32, 96, 160, 176, 208, 224, 288, 304, 312, 368, 400, 456, 464, 480, 544, 560, 568, 572, 592, 600, 604, 632, 656, 672, 688, 696, 752, 784, 840, 848, 864, 880, 904, 932, 936, 944, 964, 968, 976, 992, 1056, 1072, 1080, 1084, 1086, 1104, 1112, 1116, 1118, 1128 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..50.

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 len(newb) > 0 and newb[0] == '1' and newb == newb[::-1]:

                return (digs_to_remove == 5)

    return False

print(list(filter(ok, range(1129)))) # Michael S. Branicky, Aug 15 2021

CROSSREFS

Sequence in context: A208635 A259715 A195088 * A044219 A044600 A189884

Adjacent sequences:  A050426 A050427 A050428 * A050430 A050431 A050432

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

EXTENSIONS

Data corrected and extended by Sean A. Irvine, Aug 15 2021

STATUS

approved

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Last modified October 28 17:39 EDT 2021. Contains 348329 sequences. (Running on oeis4.)