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A169843
EKG sequence started at 6 instead of 2.
13
6, 2, 4, 8, 10, 5, 15, 3, 9, 12, 14, 7, 21, 18, 16, 20, 22, 11, 33, 24, 26, 13, 39, 27, 30, 25, 35, 28, 32, 34, 17, 51, 36, 38, 19, 57, 42, 40, 44, 46, 23, 69, 45, 48, 50, 52, 54, 56, 49, 63, 60, 55, 65, 70, 58, 29, 87, 66, 62, 31, 93, 72, 64, 68, 74, 37, 111, 75, 78, 76, 80, 82, 41
OFFSET
1,1
COMMENTS
A generalization of A064413.
MATHEMATICA
f[s_List] := Block[{m = s[[-1]], k = 3}, While[MemberQ[s, k] || GCD[m, k] == 1, k++]; Append[s, k]]; Nest[f, {6, 2}, 71] (* Michael De Vlieger, Jan 21 2016, after Robert G. Wilson v at A064413 *)
PROG
(Python)
from math import gcd
def aupton(terms):
alst, aset = [1, 6], {1, 6}
for n in range(2, terms+1):
k = 2
while True:
while k in aset: k += 1
if gcd(alst[-1], k) != 1: alst.append(k); aset.add(k); break
k += 1
return alst[1:]
print(aupton(73)) # Michael S. Branicky, Jun 02 2021
CROSSREFS
For other initial terms, see A064413, A169837, A169839, A169841, A169845, A169847, A169849, A169851, A169853, A169855.
Sequence in context: A156590 A135617 A019930 * A329591 A123139 A027599
KEYWORD
nonn
AUTHOR
T. D. Noe and N. J. A. Sloane, Jun 02 2010
STATUS
approved

  NODES
orte 1
see 2
Story 1