SPOJ.com - Problem LCMSUM

LCMSUM - LCM Sum

#number-theory

Given n, calculate the sum LCM(1, n) + LCM(2, n) + .. + LCM(n, n), where LCM(i, n) denotes the Least Common Multiple of the integers i and n.

The first line contains T the number of test cases. Each of the next T lines contain an integer n.

Output T lines, one for each test case, containing the required sum.

Sample Input:
3
1
2
5

Sample Output:
1
4
55

1 <= T <= 300000
1 <= n <= 1000000

< Previous 1 2 3 4 5 Next >

	adhikari vushesh babu: 2013-09-20 20:53:58 At last green light :) use scanf and printf instead of cin and cout which costed me many TLE.
	Ouditchya Sinha: 2013-04-29 08:40:16 Great Problem! Learnt a lot about totient function... But I think there's some server instability, my earlier solution ran in 4.19s on ideone & here it TLE'd, my improved solution ran in 0.42s on ideone & here it took 4.13s. Strange. :)
	Rajarshi Sarkar: 2013-04-29 06:55:43 One does not simply calculate LCM :D
	saket diwakar: 2013-01-30 23:14:57 finally got AC....:) same algo getting TLE in python..#strange Last edit: 2013-01-30 23:16:40
	Benjamin Pinaya: 2012-02-21 04:17:08 One does not simply uses Java in Spoj <Boromir> :D
	David: 2011-12-23 04:11:57 Not enough time or too many test cases for Java. Precompute sum for all n from 1 to 1000000 and store results in array. Elapsed time for this effort is 0.250 sec. Still get TLE. Java I/O too slow. Sigh. Last edit: 2011-12-23 04:12:37

Added by:	Varun Jalan
Date:	2010-01-24
Time limit:	1s
Source limit:	50000B
Memory limit:	1536MB
Cluster:	Cube (Intel G860)
Languages:	All except: PERL6
Resource:	own problem used for Codechef Snackdown Onsite