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A272670 Numbers whose binary expansion is not palindromic but which when reversed and leading zeros omitted, does form a palindrome. 3
2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24, 28, 30, 32, 34, 36, 40, 42, 48, 54, 56, 60, 62, 64, 66, 68, 72, 80, 84, 90, 96, 102, 108, 112, 120, 124, 126, 128, 130, 132, 136, 144, 146, 160, 168, 170, 180, 186, 192, 198, 204, 214, 216, 224, 238, 240, 248, 252, 254 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Decimal interpretation of A273245. Twice A057890.

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

MAPLE

isPal := proc(L::list)

    local i;

    for i from 1 to nops(L)/2 do

        if op(i, L) <> op(-i, L) then

            return false;

        end if;

    end do:

    true ;

end proc:

isA272670 := proc(n)

    local bdgs ;

    bdgs := convert(n, base, 2) ;

    if isPal(bdgs) then

        return false;

    else

        A000265(n) ;

        bdgs := convert(%, base, 2) ;

        isPal(bdgs) ;

    end if;

end proc:

for n from 1 to 500 do

    if isA272670(n) then

        printf("%d, ", n) ;

    end if;

end do: # R. J. Mathar, May 20 2016

PROG

(Python)

A272670_list = [n for n in range(1, 10**4) if bin(n)[2:] != bin(n)[:1:-1] and bin(n)[2:].rstrip('0') == bin(n)[:1:-1].lstrip('0')] # Chai Wah Wu, May 21 2016

CROSSREFS

Cf. A006995, A057890, A273245, A273329, subsequence of A154809.

Sequence in context: A029741 A240171 A221284 * A234521 A085125 A251237

Adjacent sequences:  A272667 A272668 A272669 * A272671 A272672 A272673

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane, May 19 2016

STATUS

approved

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Last modified July 12 10:09 EDT 2020. Contains 335657 sequences. (Running on oeis4.)