ITRIX12E - R Numbers


R - Numbers

R-numbers are numbers which have the property that they do not have the digit '0' and sum of every two adjacent digits of the number is prime. 123 is a R-number because 1+2 =3 and 2+3 =5 and 3, 5 are primes.

How many R-numbers can be formed with at most length N?

i.e. R-numbers of length 1 + R-numbers of length 2 + R-numbers of length 3 + ... R-numbers of length N.

Length of a number = Number of digits in the number.

Only four single digit numbers are R-numbers which are nothing but single digit primes 2, 3, 5, 7.

Input Specification

The first line of the input file contains T which denotes the number of test cases. The next T lines contain an integer N <= 10^9.

Output Specification

Print the numbers of R-numbers modulo 1000000007. [10^9+7];

Example

Sample Input:
2
1
2

Sample Output:
4
33

hide comments
ranjith13: 2023-06-23 06:33:16

Can someone help me why its giving run time and what is better optimisation for this solution
<snip>
[Simes]: this is not the place for a code review, use the forum.

Last edit: 2023-06-23 08:09:50
smso: 2021-07-20 13:30:31

Used G.P. sum with common ratio in the form of matrix.

harshit2202: 2019-03-16 08:41:34

I can find it for particular N in log N
How to find it for atmost N because is N is too large

shahianshu: 2018-10-07 09:41:51

Amazing problem , solved using linear recurrence relation :)

masterchef2209: 2018-09-08 14:40:48

ONE HELL OF A QUESTION

arnauddesombre: 2018-08-23 17:36:48

(correct) answers for a few values of n:
1: 4
2: 33
3: 130
4: 454
5: 1545
10: 663370
100: 26514125
1000: 906016252
10000: 396515823
100000: 827019605
1000000: 294370820
10000000: 29572369
100000000: 530109085
1000000000: 757510247

narutorocks: 2016-06-03 09:16:25

NICE QUESTION LEARNT A LOT

harkirat: 2016-05-15 08:59:27

@david : wrong

David: 2013-09-24 20:17:39

Sorry - my bad and WA at the time.
IP:
3
3
4
5

OP:
130
454
1545

Last edit: 2021-04-06 19:23:47
(Tjandra Satria Gunawan)(曾毅昆): 2012-04-17 14:42:15

Finally I got AC...
@Aman Kumar: Thanks ;)


Added by:Radhakrishnan Venkataramani
Date:2012-03-12
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:Own problem