A206528 5^n concatenated with itself.
11, 55, 2525, 125125, 625625, 31253125, 1562515625, 7812578125, 390625390625, 19531251953125, 97656259765625, 4882812548828125, 244140625244140625, 12207031251220703125, 61035156256103515625, 3051757812530517578125, 152587890625152587890625
Offset: 0
Examples
a(1)=55 because 5^1 concatenated with 5^1 is 55.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
Programs
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Magma
[Seqint(Intseq(5^n) cat Intseq(5^n)): n in [0..20]];
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Mathematica
Table[FromDigits[Join[IntegerDigits[5^n],IntegerDigits[5^n]]],{n,0,20}]
Formula
a(n) = A020338(5^n).