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A331896 Positive numbers all of whose divisors are negabinary palindromes (A331891). 2
1, 3, 5, 7, 11, 17, 21, 23, 31, 43, 51, 77, 85, 103, 127, 155, 211, 217, 233, 257, 301, 341, 479, 635, 683, 739, 771, 857, 889, 937, 1117, 1229, 1285, 1333, 1367, 1799, 1951, 2111, 2159, 2383, 2395, 2459, 2731, 2827, 3187, 3251, 3347, 3937, 4001, 4273, 4369 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

21 is a term since all the divisors of 21, {1, 3, 7, 21}, are palindromes in negabinary representation: {1, 111, 11011, 10101}.

MATHEMATICA

negabin[n_] := negabin[n] = If[n==0, 0, negabin[Quotient[n-1, -2]]*10 + Mod[n, 2]]; nbPalinQ[n_] := PalindromeQ @ negabin[n]; negaBinAllDivPalQ[n_] := nbPalinQ[n] && AllTrue[Most @ Divisors[n], nbPalinQ]; Select[Range[5000], negaBinAllDivPalQ]

CROSSREFS

Cf. A039724, A062687, A329419, A331891.

Sequence in context: A152998 A222176 A331891 * A108539 A170886 A238137

Adjacent sequences:  A331893 A331894 A331895 * A331897 A331898 A331899

KEYWORD

nonn,base

AUTHOR

Amiram Eldar, Jan 30 2020

STATUS

approved

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Last modified June 21 06:24 EDT 2021. Contains 345358 sequences. (Running on oeis4.)