A342038 a(n) is the index of the first occurrence of prime(n) in A307437.
1, 2, 3, 5, 6, 4, 9, 11, 7, 15, 18, 20, 21, 23, 13, 29, 30, 33, 35, 12, 39, 41, 22, 16, 25, 17, 53, 54, 28, 63, 65, 34, 69, 37, 75, 78, 81, 83, 43, 89, 45, 19, 32, 49, 99, 105, 111, 113, 38, 58, 119, 60, 125, 64, 131, 67, 135, 138, 70, 47, 73, 153, 31, 52, 79
Offset: 2
Keywords
Examples
For n = 7, prime(n) = 17. The first k such that: (i) C_(2k) is a subgroup of (Z/17Z)*; (ii) there is no m < 17 such that C_(2k) is a subgroup of (Z/mZ)* is k = 4, so a(7) = 4. For n = 21, prime(n) = 73. The first k such that: (i) C_(2k) is a subgroup of (Z/73Z)*; (ii) there is no m < 73 such that C_(2k) is a subgroup of (Z/mZ)* is k = 12, so a(21) = 12.
Links
- Jianing Song, Table of n, a(n) for n = 2..500
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