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A332798 Numbers whose smallest prime factor is 19. 6
19, 361, 437, 551, 589, 703, 779, 817, 893, 1007, 1121, 1159, 1273, 1349, 1387, 1501, 1577, 1691, 1843, 1919, 1957, 2033, 2071, 2147, 2413, 2489, 2603, 2641, 2831, 2869, 2983, 3097, 3173, 3287, 3401, 3439, 3629, 3667, 3743, 3781, 4009, 4237, 4313, 4351, 4427 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The asymptotic density of this sequence is 3072/323323. - Amiram Eldar, Dec 06 2020
REFERENCES
Emmanuel Desurvire, Classical and Quantum Information Theory: An Introduction for the Telecom Scientist, Cambridge University Press, 2009, table 20.5 p. 421.
LINKS
FORMULA
a(n) = 19*A166061(n).
EXAMPLE
a(2) = 19*19, a(3) = 19*23.
MATHEMATICA
19 * Select[Range[235], CoprimeQ[#, 510510] &] (* Amiram Eldar, Feb 24 2020 *)
PROG
(Rexx)
P = 19 ; S = P
do N = P by 2 while length( S ) < 255
do I = 1 until P = X
X = PRIME( I )
if P = X then leave I
if N // X = 0 then iterate N
end I
S = S || ', ' P*N
end N
say S ; return S
CROSSREFS
Cf. A084967 (5), A084968 (7), A084969 (11), A084970 (13), A332799 (17), A332797 (23), A166061 (19-rough numbers).
Sequence in context: A192568 A171324 A078368 * A209227 A208504 A207877
KEYWORD
nonn,easy
AUTHOR
Frank Ellermann, Feb 24 2020
STATUS
approved

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Last modified February 21 20:41 EST 2024. Contains 370237 sequences. (Running on oeis4.)