The On-Line Encyclopedia of Integer Sequences (OEIS)

A364956 revision #15

A364956

Numbers k such that A163511(k) is either k itself or its descendant in Doudna-tree, A005940 (or equally, in A163511-tree).

1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192, 256, 384, 512, 768, 1024, 1536, 2048, 3072, 4096, 6144, 8192, 12288, 16384, 24576, 32768, 49152, 65536, 98304, 131072, 196608, 262144, 341887, 393216, 524288, 683774, 786432, 1048576, 1572864, 2097152, 2495625, 3145728, 4194304, 4991250, 6291456

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Numbers k such that A252464(k) = A364954(k), where A364954(n) is the length of the common prefix in the binary expansions of A156552(n) and A156552(A163511(n)).

LINKS

Table of n, a(n) for n=1..49.

EXAMPLE

For n = 341887, A156552(n) = 1736, "11011001000" in binary, and A163511(n) = 1830711541, with A156552(A163511(n)) = 444544, "1101100100010000000" in binary, and as the former binary expansion is a prefix of the latter, 341887 is included in this sequence. In this case, 1830711541 = A003961^7(2*341887), where A003961^7 indicates a prime shift by seven steps towards larger primes.

For n = 683774 = 2*341887, A156552(n) = 3473 = "110110010001", and A163511(n) = 3661423082 = 2*1830711541, with A156552(A163511(n)) = 889089, "11011001000100000001", and as the former binary expansion is a prefix of the latter, 683774 is included in this sequence.

For n = 1367548 = 4*341887, A156552(n) = 6947, "1101100100011" in binary, and A163511(n) = 7322846164 = 2*3661423082 with A156552(A163511(n)) = 1778179, "110110010001000000011" in binary, as the former binary expansion is NOT a prefix of the latter, 1367548 is NOT included in this sequence.

CROSSREFS

Positions of 0's in A364955.

Cf. A005940, A156552, A163511.

Cf. A029744 (subsequence).

Cf. also A364960.

Cf. A252464, A364954.

Sequence in context: A052810 A364964 A320315 * A164090 A029744 A018635

Adjacent sequences: A364953 A364954 A364955 * A364957 A364958 A364959

KEYWORD

nonn

AUTHOR

Antti Karttunen, Sep 02 2023

STATUS

reviewed