A078232 a(1) = 2, a(n+1) = smallest multiple of a(n) using only prime digits (2,3,5,7).

2, 22, 352, 23232, 255552, 23255232, 232575575232, 22327255222272, 2752333577535325335552, 2327233352725273522727577372535775232

Offset

1,1

Comments

Sequence is infinite - see Comments in A078233. - Fung Cheok Yin (cheokyin_restart(AT)yahoo.com.hk), Sep 02 2006

Links

Table of n, a(n) for n=1..10.

Prog

(PARI) lista(nn) = my(a = 2); print1(a, ", "); for (n=2, nn, my(k=2); while(#select(x->!isprime(x), digits(k*a)), k++); a = k*a; print1(a, ", "); ); \\ Michel Marcus, Jun 23 2025

Crossrefs

Cf. A078233, A078234, A078235, A078236.

Sequence in context: A245113 A363006 A363304 * A151615 A111985 A378743

Adjacent sequences: A078229 A078230 A078231 * A078233 A078234 A078235

Keyword

base,more,nonn

Author

Amarnath Murthy, Nov 23 2002

Extensions

More terms from Sascha Kurz, Jan 06 2003

a(9) corrected by Sean A. Irvine, Jun 23 2025

a(10) from Michael S. Branicky, Jun 24 2025

Status

approved