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A028915

Take next group of 3 primes, beginning at 7, map final digits to base 4 by 1->0, 3->1, 7->3, 9->2; convert back to decimal.

49, 57, 35, 7, 24, 49, 38, 49, 57, 51, 40, 55, 24, 7, 33, 57, 32, 54, 12, 23, 7, 15, 38, 54, 27, 10, 1, 38, 49, 59, 9, 33, 15, 24, 61, 35, 30, 1, 54, 7, 16, 43, 25, 12, 39, 56, 7, 41, 57, 49, 60, 43, 13, 51, 19, 38, 1, 40, 6, 49, 54, 54, 5, 3, 17, 54, 14, 46, 24, 49

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OFFSET

2,1

COMMENTS

The index corresponds to the n-th triple of primes, thus offset is 2 since we discard the first prime triple (2,3,5).

REFERENCES

Hans Paul van den Haag used this coding in Scientific American, German Edition, 4/1996 P.23.

LINKS

Table of n, a(n) for n=2..71.

Index entries for sequences related to final digits of numbers

EXAMPLE

7,11,13 -> 7,1,3 -> 3 * 4^2 + 0 * 4^1 + 1 * 4^0 = 49.