A352722 Lexicographically earliest sequence of distinct positive integers such that a(1) = 2 and for any n > 0, a(n) AND a(n+1) is prime (where AND denotes the bitwise AND operator).
2, 3, 6, 10, 7, 5, 13, 15, 11, 18, 14, 19, 17, 21, 25, 23, 27, 34, 22, 35, 26, 38, 66, 30, 67, 31, 29, 37, 39, 45, 41, 43, 47, 53, 55, 61, 63, 59, 70, 42, 71, 50, 74, 51, 75, 54, 130, 46, 82, 131, 58, 134, 83, 49, 81, 57, 85, 133, 69, 135, 77, 73, 79, 87, 91
Offset: 1
Examples
The first terms, alongside the corresponding prime numbers, are: n a(n) a(n) AND a(n+1) -- ---- --------------- 1 2 2 2 3 2 3 6 2 4 10 2 5 7 5 6 5 5 7 13 13 8 15 11 9 11 2 10 18 2
Links
- Rémy Sigrist, Table of n, a(n) for n = 1..10000
Programs
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PARI
s=0; v=2; for (n=1, 65, print1 (v", "); s+=2^v; for (w=1, oo, if (!bittest(s, w) && isprime(bitand(v,w)), v=w; break)))
Comments