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A249559 Same definition as A247665, except first term is 3. 1
3, 2, 5, 7, 4, 9, 11, 13, 17, 19, 8, 23, 15, 29, 31, 37, 41, 43, 47, 49, 53, 59, 16, 61, 67, 71, 25, 27, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 91, 131, 137, 139, 149, 151, 32, 157, 163, 167, 173, 179, 181, 191, 85, 193, 57, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
PROG
(SageMath) # from Nadia Heninger, Oct 28 2014: s is the starting point (2 in A247665, 3 here).
def gen(s):
sequence = [s]
available = range(2, 2*s)
available.pop(available.index(s))
yield s
while True:
available.extend(range(available[-1]+1, next_prime(available[-1])+1))
for i, e in enumerate(available):
if all([gcd(e, sequence[j])==1 for j in range(-len(sequence)/2, 0)]):
available.pop(i)
sequence.append(e)
yield(e)
break
g = gen(3)
[g.next() for i in range(40)] (gets first 40 terms)
(Python)
from itertools import count, islice
from math import gcd
from collections import deque
def A249559_gen(): # generator of terms
aset, aqueue, c, f = {3}, deque([3]), 2, True
yield 3
while True:
for m in count(c):
if m not in aset and all(gcd(m, a) == 1 for a in aqueue):
yield m
aset.add(m)
aqueue.append(m)
if f: aqueue.popleft()
f = not f
while c in aset:
c += 1
break
A249559_list = list(islice(A249559_gen(), 50)) # Chai Wah Wu, May 19 2022
CROSSREFS
Cf. A247665.
Sequence in context: A338744 A338745 A203602 * A182846 A292962 A069196
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 02 2014
STATUS
approved

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)