The On-Line Encyclopedia of Integer Sequences (OEIS)

A364956 revision #12

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

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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 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.

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

approved