The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

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