This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a:= proc(n) option remember; `if`(n=1, 1, (s-> parse(cat(
seq(parse(s[i])*5, i=1..length(s)))))(""||(a(n-1))))
end:
seq(a(n), n=1..10); # Alois P. Heinz, May 25 2018
NestList[FromDigits[Flatten[IntegerDigits/@(5*IntegerDigits[#])]]&,1,10] (* Harvey P. Dale, Dec 31 2013 *)
def A061583_first(n): an = "1" a061583 = [] while n > 1: a061583.append(int(an)) newan = "" for i in an: newan += str(5*int(i)) an = newan n -= 1 a061583.append(int(an)) return a061583 # John Cerkan, May 25 2018
NestList[FromDigits[Flatten[IntegerDigits/@(7*IntegerDigits[#])]]&,1,10] (* Harvey P. Dale, Jan 23 2015 *)
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
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
NestList[FromDigits@ Flatten@ Map[IntegerDigits, 4*IntegerDigits[#]] &, 1, 9] (* Michael De Vlieger, Feb 25 2023 *)
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