A078223 a(1) = 2, a(n+1) > a(n) is the smallest multiple of a(n) using only even digits but not divisible by 10 (i.e., having no trailing zeros).

2, 4, 8, 24, 48, 288, 864, 6048, 260064, 26266464, 40082624064, 866826828008064, 26444286042042008448, 20286626620462624006244884224, 22488068646246262608620204848404846444288, 284860000088022466828484860444044822420060828284646488064

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Mathematica

a[n_] := a[n] = Block[{k = 2, b = a[n - 1], c = 2 Range[0, 4]}, While[Mod[k*b, 10]==0 || Union@ Join[c, IntegerDigits[k*b]] != c, k++]; k*b]; a[1] = 2; Array[a, 14] (* Robert G. Wilson v, May 26 2014 *)

Crossrefs

Cf. A078221, A078222, A078224.

Sequence in context: A218861 A359039 A078222 * A291405 A306420 A361726

Adjacent sequences: A078220 A078221 A078222 * A078224 A078225 A078226

Keyword

nonn,base

Author

Amarnath Murthy, Nov 23 2002

Extensions

More terms from Sascha Kurz, Jan 06 2003

a(14) from Jon E. Schoenfield, Jun 04 2007

a(15) from Chai Wah Wu, Nov 20 2019

a(16) from Chai Wah Wu, Nov 29 2019

Status

approved