A044836 -id:A044836 - cp's OEIS frontend

A338754 Duplicate each decimal digit of n, so 0 -> 00, ..., 9 -> 99.

0, 11, 22, 33, 44, 55, 66, 77, 88, 99, 1100, 1111, 1122, 1133, 1144, 1155, 1166, 1177, 1188, 1199, 2200, 2211, 2222, 2233, 2244, 2255, 2266, 2277, 2288, 2299, 3300, 3311, 3322, 3333, 3344, 3355, 3366, 3377, 3388, 3399, 4400, 4411, 4422, 4433, 4444, 4455, 4466

Offset: 0

Kevin Ryde, Nov 06 2020

This is equivalent to changing decimal digits 0,1,..,9 to base 100 digits 0,11,..,99, so the sequence is numbers which can be written in base 100 using only digits 0,11,..,99. Also, numbers whose decimal digit runs are all even lengths (including 0 as no digits at all).

This sequence first differs from A044836 (apart from term 0) at a(100) = 110000 whereas A044836(100) = 10011, because A044836 allows odd length digit runs provided there are more even than odd.

			For n=5517, digits duplicate to a(n) = 55551177.

Kevin Ryde, Table of n, a(n) for n = 0..10000

Cf. A051022 (0 above each digit), A044836.

Other bases: A001196, A338086.

PARI
```
a(n) = fromdigits(digits(n),100)*11;
```

def A338754(n): return int(''.join(d*2 for d in str(n))) # Chai Wah Wu, May 07 2022

a(n) = Sum_{i=0..k} 11*d[i]*100^i where the decimal expansion of n is n = Sum_{i=0..k} d[i]*10^i with digits 0 <= d[i] <= 9.

a(n) = A051022(n)*11 for n > 0. - Kritsada Moomuang, Oct 20 2019

A044828 Positive integers having more base-2 runs of even length than odd.

Original entry on oeis.org

3, 12, 15, 19, 25, 27, 48, 51, 60, 63, 67, 76, 79, 97, 99, 100, 102, 103, 108, 111, 115, 121, 123, 147, 153, 155, 179, 192, 195, 201, 203, 204, 205, 207, 211, 217, 219, 240, 243, 252, 255, 259, 268, 271, 304, 307, 316, 319, 385

Offset: 1

Clark Kimberling

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A044836 (for base 10).

meQ[n_]:=Module[{b=Boole[EvenQ[Length/@Split[IntegerDigits[n,2]]]]}, Count[ b,1]> Length[b]/2]; Select[Range[400],meQ] (* Harvey P. Dale, Aug 02 2013 *)

A248126 a(n) = n^2 with each digit repeated.

Original entry on oeis.org

11, 44, 99, 1166, 2255, 3366, 4499, 6644, 8811, 110000, 112211, 114444, 116699, 119966, 222255, 225566, 228899, 332244, 336611, 440000, 444411, 448844, 552299, 557766, 662255, 667766, 772299, 778844, 884411, 990000, 996611, 11002244, 11008899, 11115566

Offset: 1

Jon Perry, Nov 01 2014

Inspired by A116699.

			13^2 = 169, so a(13) = 116699.

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Cf. A020338, A044836.

Cf. A116699, A338754.

for (i=1;i<40;i++) {
s=(i*i).toString();
for (j=0;j

a248126[n_Integer] :=
Module[{m}, m := IntegerDigits[n^2];
  FromDigits[Flatten[Transpose[List[m, m]]]]]; a248126 /@ Range[34] (* Michael De Vlieger, Nov 06 2014 *)
Table[FromDigits[Riffle[id=IntegerDigits[n^2],id]],{n,40}] (* Harvey P. Dale, Dec 19 2015 *)

a(n)= my(d = 11*digits(n^2)); fromdigits(d, 100) \\ David A. Corneth, Dec 02 2023

def a(n): return int("".join(d*2 for d in str(n**2)))
print([a(n) for n in range(1, 35)]) # Michael S. Branicky, Dec 02 2023

cp's OEIS Frontend

A338754 Duplicate each decimal digit of n, so 0 -> 00, ..., 9 -> 99.

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A044828 Positive integers having more base-2 runs of even length than odd.

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A248126 a(n) = n^2 with each digit repeated.

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