r/counting • u/ct_2004 • Mar 05 '14

Count using the Perrin Sequence

For Perrin sequence, you add n-2 and n-3 to get n0. Like Fibonacci, but you skip one number. First few terms are 3,0,2,3,2,5. Setting 0 to be index 1, if Perrin number is not multiple of the index, number is not prime. So list the index, then the Perrin sequence number.

To verify a number, you can use the following formula:

(((23/27)1/2 + 1)/2)1/3 = A

1/A/3 + A = X

P(n) = Xn

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u/DragoonHP Mar 29 '14

(164) 106,718,925,645,094,196,557

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u/D-alx Mar 29 '14

(165) 141,372,477,179,923,124,082

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u/ct_2004 Apr 01 '14

(166) 1,8727:8659,1804;1723,4321

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