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A329877
Lexicographically earliest sequence of positive integers such that for n > 1, the concatenation of a(n), a(n-1), ..., a(1), in binary, is a prime number.
1
1, 1, 1, 2, 4, 3, 7, 10, 18, 1, 13, 5, 2, 42, 3, 3, 22, 18, 23, 15, 29, 33, 23, 17, 5, 33, 3, 134, 94, 84, 6, 57, 103, 13, 92, 63, 90, 60, 156, 39, 10, 108, 114, 65, 78, 67, 52, 57, 11, 21, 114, 79, 366, 128, 76, 22, 382, 36, 88, 34, 68, 110, 2, 72, 14, 28
OFFSET
1,4
COMMENTS
This sequence is a binary variant of A329876.
For any n > 0, the binary concatenation of a(n+1) and A329875(n) gives A329875(n+1).
EXAMPLE
The first terms, alongside their binary representations and the corresponding concatenations, are:
n a(n) bin(a(n)) bin(A329875(n))
-- ---- --------- -----------------------
1 1 1 1
2 1 1 11
3 1 1 111
4 2 10 10111
5 4 100 10010111
6 3 11 1110010111
7 7 111 1111110010111
8 10 1010 10101111110010111
9 18 10010 1001010101111110010111
10 1 1 11001010101111110010111
PROG
(PARI) print1 (v=1); for (n=2, 69, s=(b=2)^#digits(v, b); for (k=1, oo, if (isprime(v+=s), print1 (", "k); break)))
CROSSREFS
See A329875 for the corresponding concatenations.
Cf. A329876.
Sequence in context: A207633 A177877 A090568 * A223625 A166017 A257504
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Nov 23 2019
STATUS
approved