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A350095 a(n) is the smaller of 2 consecutive primes bounding an interval containing a record number A350097(n) of odd squarefree semiprimes (A046388). 3
13, 31, 89, 199, 211, 887, 1129, 1327, 9973, 15683, 19609, 44293, 155921, 370261, 396733, 492113, 1357201, 1671781, 3826019, 17836409, 20831323, 47465267, 107534587, 122164747, 434865437, 436273009, 2300942549, 4302407359, 10726904659, 25056082087, 42652618343 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Lucas A. Brown, Table of n, a(n) for n = 1..32 (terms 1-28 from Hugo Pfoertner, 29-31 from Martin Ehrenstein)
Lucas A. Brown, Python program.
FORMULA
A350096(n) = nextprime(a(n)).
EXAMPLE
a(1) = 13: semiprime 15 < 17 = nextprime(a(1)) = A350096(1);
a(2) = 31: semiprimes 33, 35 < 37 = A350096(2);
a(6) = 887: semiprimes 889, 893, 895, 899, 901, 905 < 907 = A350096(6);
a(7) = 1129: semiprimes 1133, 1135, 1137, 1139, 1141, 1145, 1147, 1149 < 1151 = A350096(7);
a(8) = 1327: semiprimes 1329, 1333, 1337, 1339, 1343, 1345, 1347, 1349, 1351, 1355, 1357 < 1361 = A350096(8).
CROSSREFS
A350096 are the upper ends of the intervals, A350097 are the corresponding counts of odd squarefree semiprimes in the intervals.
Sequence in context: A335732 A342706 A095379 * A160772 A271575 A039403
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Dec 25 2021
EXTENSIONS
a(29)-a(31) from Martin Ehrenstein, Dec 28 2021
a(32) from Lucas A. Brown, Mar 21 2024
STATUS
approved

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Last modified June 14 21:35 EDT 2024. Contains 373401 sequences. (Running on oeis4.)