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A078234
a(1) = 5, a(n+1) is the smallest multiple of a(n) using only prime digits (2,3,5,7).
3
5, 25, 75, 225, 3375, 57375, 2352375, 322275375, 27757255773375, 23322552325375373733375, 5272277223223332755233325327375733375
OFFSET
1,1
COMMENTS
Sequence is infinite - see Comments in A078233. - Fung Cheok Yin (cheokyin_restart(AT)yahoo.com.hk), Sep 02 2006
PROG
(Python)
def pd(n): return set(str(n)) <= set("2357") # has only prime digits
def aupton(terms, startat=5):
alst = [startat]
for n in range(2, terms+1):
m = alst[-1]; km = 2*m
while not pd(km): km += m
alst.append(km)
return alst
print(aupton(9)) # Michael S. Branicky, May 25 2021
CROSSREFS
KEYWORD
base,nonn,more
AUTHOR
Amarnath Murthy, Nov 23 2002
EXTENSIONS
More terms from Sascha Kurz, Jan 06 2003
a(10) from Robert Gerbicz, May 09 2008
a(11) from Michael S. Branicky, May 25 2021
STATUS
approved