A078233 a(1) = 3, a(n+1) = smallest multiple of a(n) using only prime digits(2,3,5,7).

3, 27, 2322, 733752, 5327773272, 32322753325273752, 3575237337322577275537537272

Offset

1,1

Comments

The sequence is infinite. Proof by contradiction: Assume a(n) is the last term of the sequence. If m is an integer such that 10^{m-1} +1 < a(n) < 10^m +1 then a(n) * (10^m +1) is a multiple of a(n) using only prime digits. - Fung Cheok Yin (cheokyin_restart(AT)yahoo.com.hk), Sep 02 2006

Links

Table of n, a(n) for n=1..7.

Crossrefs

Cf. A078232, A078234, A078235, A078236.

Sequence in context: A051576 A184278 A158113 * A009039 A137092 A122215

Adjacent sequences: A078230 A078231 A078232 * A078234 A078235 A078236

Keyword

base,more,nonn

Author

Amarnath Murthy, Nov 23 2002

Extensions

More terms from Sascha Kurz, Jan 06 2003

One more term from Fung Cheok Yin (cheokyin_restart(AT)yahoo.com.hk), Sep 02 2006

a(7) from Robert Gerbicz, May 09 2008

Status

approved