

A145092


Indices of the prime numbers after mapping the positive integers onto successive rings of length {1, 5, 30, 180, 1080, ...} and assigning index 0 to the smallest value in each.


0



0, 1, 3, 0, 4, 6, 10, 12, 16, 22, 24, 0, 4, 6, 10, 16, 22, 24, 30, 34, 36, 42, 46, 52, 60, 64, 66, 70, 72, 76, 90, 94, 100, 102, 112, 114, 120, 126, 130, 136, 142, 144, 154, 156, 160, 162, 174, 6, 10, 12, 16, 22, 24, 34, 40, 46, 52, 54, 60, 64, 66, 76, 90, 94, 96, 100, 114
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OFFSET

1,3


COMMENTS

After the second ring, all primes have indices that are congruent to 0 or 4 modulo 6, because index 0 is given to a value congruent to 1 (one greater than a power of six).


LINKS

Table of n, a(n) for n=1..67.


EXAMPLE

The first three rings contain these numbers:
1
.
2 3 4 5 6 (sequence begins here)
0 1 . 3 .
.........
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 ...
0 . . .. .4 .. .6 .. .. .. 10 .. 12 .. .. .. 16 .. .. .. .. .. 22 .. 24 .. .. .. .. ...


CROSSREFS

Cf. A000040, A008588, A016957
Sequence in context: A112238 A111493 A190181 * A210878 A320373 A303274
Adjacent sequences: A145089 A145090 A145091 * A145093 A145094 A145095


KEYWORD

easy,nonn


AUTHOR

Reikku Kulon, Oct 01 2008


STATUS

approved



