A332798 Numbers whose smallest prime factor is 19.

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

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

Amiram Eldar, Table of n, a(n) for n = 1..10000

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

Adjacent sequences: A332795 A332796 A332797 * A332799 A332800 A332801

Keyword

nonn,easy

Author

Frank Ellermann, Feb 24 2020

Status

approved