OFFSET
1,3
COMMENTS
The entries appear to occur in pairs, (6k, 6k+1). - Zak Seidov, May 31 2010. Proof from Max Alekseyev, May 31 2010: If m is an even term of A169828, then it is also divisible by 3, i.e., m=6k, and m+1 is also a term of A169828. On the other hand, if m is an odd term of A169828, then m == 1 (mod 3) and thus m=6k+1, implying that m-1 is also a term of A169828.
LINKS
Max Alekseyev, Table of n, a(n) for n = 1..30
Erich Friedman, What's Special About This Number? (See entries 1002, 1003.)
EXAMPLE
This is Maple:
convert(1002,base,2);
[0, 1, 0, 1, 0, 1, 1, 1, 1, 1]
convert(1002,base,3);
[0, 1, 0, 1, 0, 1, 1]
988496761674 = 1110011000100110111111111001001101001010 (base 2)
988496761674 = ..............10111111111001001101001010 (base 3)
26688254956950 = 110000100010111010111111101001101010110010110 (base 2)
26688254956950 = ................10111111101001101010110010110 (base 3)
MAPLE
f:=proc(n) local t2, t3, i, t0; t0:=1; t2:=convert(n, base, 2); t3:=convert(n, base, 3);
for i from 1 to nops(t3) do if t2[i] <> t3[i] then t0:=-1; fi; od; t0; end;
t4:=[]; for n from 1 to 20000 do if f(n) = 1 then t4:=[op(t4), n]; fi; od: t4;
CROSSREFS
KEYWORD
base,nonn
AUTHOR
N. J. A. Sloane, May 30 2010
EXTENSIONS
a(5)-a(6) from Zak Seidov and D. S. McNeil, May 31 2010
a(7)-a(8) from Alois P. Heinz, May 31 2010
a(9)-a(12) from Ray Chandler, Jun 01 2010
a(11)-a(30) from Max Alekseyev, Jun 01 2010, Sep 21 2016, Aug 26 2020
STATUS
approved