A179075 Concatenation of the first n numbers in base n.

6, 48, 436, 4855, 67146, 1120882, 21913032, 490328973, 12345678910, 345227121316, 10610896401084, 355457590375459, 12887297856859986, 502684312937210790, 20988295479420645136, 933876701895122362393, 44111544001370512713990, 2204350295349917301461848

Offset: 2

Author

Jonathan Vos Post, Jun 27 2010

Keywords

• easy
• nonn
• base

Comments

Always divisible by n, hence never prime.

Examples

			a(2) = 110 (base 2) = 6 (base 10) = A047778(2).
a(3) = 1210 (base 3) = 48 (base 10) = A048435(3).
a(4) = 12310 (base 4) = 436 (base 10) = A048436(4).
a(5) = 123410 (base 5) = 4855 (base 10) = A048437(5).
a(11) = 123456789A10 (base 11) = 345227121316 (base 10).
a(16) = 123456789ABCDE10 (base 16) = 20988295479420645136 (base 10) = A048447(16).
		

Crossrefs

Cf. A047778, A048435-A048447, A179069.

Programs

PARI

{for(n=2,19,tlt=0;
for(i=1,n-1,tlt=tlt+i*(n^(n+1-i)));
print1(tlt+n, ", ") )} \\ Douglas Latimer, May 10 2012

Formula

a(n) = n + sum(i*(n^(n+1-i)), i=1..n-1).

Extensions

Edited (errors corrected, sequence extended) by Jon E. Schoenfield, Jul 05 2010 and Jul 06 2010

More terms from Douglas Latimer, May 10 2012