A078222 a(1) = 2, a(n+1) > a(n) is the smallest multiple of a(n) using only even digits.
2, 4, 8, 24, 48, 240, 480, 2400, 4800, 24000, 48000, 240000, 480000, 2400000, 4800000, 24000000, 48000000, 240000000, 480000000, 2400000000, 4800000000, 24000000000, 48000000000, 240000000000, 480000000000, 2400000000000
Offset: 1
Links
- Index entries for linear recurrences with constant coefficients, signature (0, 10).
Crossrefs
Cf. A078221.
Programs
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Mathematica
Join[{2,4,8},Flatten[Table[{24,48}10^n,{n,0,20}]]] (* Harvey P. Dale, May 01 2013 *)
Formula
From Chai Wah Wu, Nov 20 2019: (Start)
a(n) = 10*a(n-2) for n > 5.
G.f.: x*(32*x^4 + 16*x^3 + 12*x^2 - 4*x - 2)/(10*x^2 - 1). (End)
Extensions
More terms from Sascha Kurz, Jan 04 2003
Comments