A074108 Smallest number such that the concatenation of first n terms is a proper multiple of the concatenation of first n natural numbers.

2, 4, 6, 8, 13585, 81504, 959339, 3715372, 78137091, 2037878170, 861472331456, 35628332614704, 2509243979641006, 97463093398309010, 52748900893862397840, 7355609995400651988940, 1755796374216684779591144, 71520859355651043708177774

Offset

0,1

Links

Table of n, a(n) for n=0..17.

Example

24 = 8*12, 246 = 2*123, 2468= 2*1234, 246813585 = 19993*12345 and 246813585 is a concatenation of first five terms.

Crossrefs

Sequence in context: A030149 A083146 A306091 * A231408 A361973 A021409

Adjacent sequences: A074105 A074106 A074107 * A074109 A074110 A074111

Keyword

base,nonn

Author

Amarnath Murthy, Aug 26 2002

Extensions

Corrected and extended by Max Alekseyev, May 11 2009

Status

approved