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

2,1

Comments

Always divisible by n, hence never prime.

Links

Table of n, a(n) for n=2..19.

Formula

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

Example

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).

Prog

(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

Crossrefs

Cf. A047778, A048435-A048447, A179069.

Sequence in context: A345077 A244038 A037184 * A175916 A231104 A085457

Adjacent sequences: A179072 A179073 A179074 * A179076 A179077 A179078

Keyword

easy,nonn,base

Author

Jonathan Vos Post, Jun 27 2010

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

Status

approved