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### #Actualmr_malee

Posted 13 August 2014 - 05:48 PM

hello again, I've got another interesting sequence problem, more of a difficult pattern this time (imo)

given this sequence of numbers: 1, 5, 10, 30, 60, 300, 600, 1800, 3600, 18000, 36000

can you find a way (without arrays) to return one of these numbers based on an index (1, 2, 3, 4, 5, 6, 7...)?

ignoring 1. The sequence is separated into pairs of double size numbers:

(5, 10)

(30, 60)

(300, 600)

(1800, 3600)

(18000, 36000)

pairs are separated by a multiplication of the preceding number:

1 * 5 = 5

10 * 3 = 30

60 * 5 = 300

600 * 3 = 1800

3600 * 5 = 18000

I'm almost positive there needs to be some tricky modulus going on, but can't seem to crack it.

The very difficult problem is given only an index "7", and the first number real number "5". How do you get 1800.

### #1mr_malee

Posted 13 August 2014 - 05:29 PM

hello again, I've got another interesting sequence problem, more of a difficult pattern this time (imo)

given this sequence of numbers: 1, 5, 10, 30, 60, 300, 600, 1800, 3600, 18000, 36000

can you find a way (without arrays) to return one of these numbers based on an index (1, 2, 3, 4, 5, 6, 7...)?

ignoring 1. The sequence is separated into pairs of double size numbers:

(5, 10)

(30, 60)

(300, 600)

(1800, 3600)

(18000, 36000)

pairs are separated by a multiplication of the preceding number:

1 * 5 = 5

10 * 3 = 30

60 * 5 = 300

600 * 3 = 1800

3600 * 5 = 18000

I'm almost positive there needs to be some tricky modulus going on, but can't seem to crack it.

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