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A061585
a(1) = 1, a(n)= number obtained by replacing each digit of a(n-1) with seven times its value.
4
1, 7, 49, 2863, 14564221, 72835422814147, 49145621352814145672872849, 286372835421472135145672872835424914564914562863, 1456422149145621352814728491472135728354249145649145621352814286372835422863728354214564221
OFFSET
1,2
LINKS
MATHEMATICA
NestList[FromDigits[Flatten[IntegerDigits/@(7*IntegerDigits[#])]]&, 1, 10] (* Harvey P. Dale, Jan 23 2015 *)
PROG
(PARI) A061585(n=2, a=1, m=7)={while(n--, a=eval(concat(apply(t->Str(t), digits(a)*m)))); a} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016
(Python)
def A061585_first(n):
an = "1"
a061585 = []
while n > 1:
a061585.append(int(an))
newan = ""
for i in an:
newan += str(7*int(i))
an = newan
n -= 1
a061585.append(int(an))
return a061585 # John Cerkan, May 25 2018
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, May 13 2001
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001
Corrected by Harvey P. Dale, Jan 23 2015
STATUS
approved