A105814 a(n) = n^2 + (n concatenated with n).

12, 26, 42, 60, 80, 102, 126, 152, 180, 1110, 1232, 1356, 1482, 1610, 1740, 1872, 2006, 2142, 2280, 2420, 2562, 2706, 2852, 3000, 3150, 3302, 3456, 3612, 3770, 3930, 4092, 4256, 4422, 4590, 4760, 4932, 5106, 5282, 5460, 5640, 5822, 6006, 6192, 6380, 6570

Offset: 1

Author

Eric Angelini, May 05 2005

Keywords

• base
• easy
• nonn

Examples

			1 + 11 = 12, 4 + 22 = 26, 9 + 33 = 42, 16 + 44 = 60, ..., 100 + 1010 = 1110.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A020338.

Programs

Magma

[Seqint(Intseq(n) cat Intseq(n))+n^2: n in [1..50]]; // Vincenzo Librandi, Jul 31 2015

Magma

[n^2+n*(1+10^(1+Floor(Log(n)/Log(10)))): n in [1..50]]; // Vincenzo Librandi, Jul 31 2015

Maple

seq(n^2 + n*(1+10^(1+ilog10(n))),n=1..100); # Robert Israel, Jul 30 2015

Mathematica

f[n_] := Block[{id = IntegerDigits[n]}, n^2 + FromDigits[ Join[id, id]]]; Table[ f[n], {n, 45}] (* Robert G. Wilson v, May 10 2005 *)

PARI

vector(50, n, n^2 + eval(Str(n,n))) \\ Michel Marcus, Jul 31 2015

Python

def a(n): return n**2 + int(str(n)*2)
print([a(n) for n in range(1, 47)]) # Michael S. Branicky, Dec 26 2021

Formula

a(n) = n^2 + n*(1+10^(1+floor(log_10(n)))). - Robert Israel, Jul 30 2015

a(n) = n^2 + A020338(n). - Michel Marcus, Jul 31 2015

Extensions

More terms from Robert G. Wilson v, May 10 2005