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A352186
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The numbers k arising in A352185.
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3
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1, 4, 1, 5, 5, 12, 1, 1, 1, 19, 19, 19, 19, 19, 19, 19, 19, 27, 27, 47, 47, 47, 47, 14, 14, 14, 14, 14, 67, 67, 67, 67, 67, 173, 173, 211, 211, 211, 211, 15, 15, 15, 15, 15, 15, 214, 214, 214, 214, 214, 385, 385, 385, 385, 385, 385, 385, 22, 22, 22, 22, 22, 22, 22
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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Michael S. Branicky, Table of n, a(n) for n = 1..232
Richard K. Guy, What are the smallest arithmetic progressions of composite numbers?, Amer. Math. Monthly, Vol. 93, No. 8 (1986), p. 627.
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PROG
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(Python)
from math import gcd
from sympy import isprime
from itertools import count, islice, takewhile
def comp(n): return not isprime(n)
def agen(): # generator of terms
n = 1
for m in count(2):
for k in range(1, m):
if gcd(k, m) != 1:
continue
ap = len(list(takewhile(comp, (i*m+k for i in count(1)))))
if ap >= n:
for i in range(n, ap+1):
yield k
n = ap + 1
print(list(islice(agen(), 64))) # Michael S. Branicky, Mar 12 2022
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CROSSREFS
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Cf. A352185.
Sequence in context: A075013 A117379 A007309 * A333341 A344027 A084890
Adjacent sequences: A352183 A352184 A352185 * A352187 A352188 A352189
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Mar 12 2022
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EXTENSIONS
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a(24) and beyond from Michael S. Branicky, Mar 12 2022.
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STATUS
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approved
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