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A334101 Numbers of the form q*(2^k), where q is one of the Fermat primes and k >= 0; Numbers n for which A329697(n) == 1. 11
3, 5, 6, 10, 12, 17, 20, 24, 34, 40, 48, 68, 80, 96, 136, 160, 192, 257, 272, 320, 384, 514, 544, 640, 768, 1028, 1088, 1280, 1536, 2056, 2176, 2560, 3072, 4112, 4352, 5120, 6144, 8224, 8704, 10240, 12288, 16448, 17408, 20480, 24576, 32896, 34816, 40960, 49152, 65537, 65792, 69632, 81920, 98304, 131074, 131584, 139264 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers k that themselves are not powers of two, but for which A171462(k) = k-A052126(k) is [a power of 2].

Numbers k such that A000265(k) is in A019434.

Squares of these numbers can be found (as a subset) in A334102, and the cubes (as a subset) in A334103.

LINKS

Table of n, a(n) for n=1..57.

FORMULA

For all n, A000120(a(n)) = 2.

PROG

(PARI)

A000265(n) = (n>>valuation(n, 2));

isA019434(n) = ((n>2)&&isprime(n)&&!bitand(n-2, n-1));

isA334101(n) = isA019434(A000265(n));

(PARI)

A052126(n) = if(1==n, n, n/vecmax(factor(n)[, 1]));

A209229(n) = (n && !bitand(n, n-1));

isA334101(n) = ((!A209229(n))&&A209229(n-A052126(n)));

CROSSREFS

Row 1 of A334100.

Cf. A000120, A000265, A052126, A171462, A209229, A329697, A334102, A334103.

Cf. A019434 (primes present), A007283, A020714, A110287 (other subsequences).

Subsequence of A018900.

Sequence in context: A140449 A207063 A230851 * A265749 A115823 A190721

Adjacent sequences:  A334098 A334099 A334100 * A334102 A334103 A334104

KEYWORD

nonn

AUTHOR

Antti Karttunen, Apr 14 2020

STATUS

approved

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Last modified April 15 01:08 EDT 2021. Contains 342971 sequences. (Running on oeis4.)