A169855 EKG sequence started at 12 instead of 2.

12, 2, 4, 6, 3, 9, 15, 5, 10, 8, 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

Author

T. D. Noe and N. J. A. Sloane, Jun 02 2010

Keywords

• nonn

Comments

A generalization of A064413.

Links

• Peter Kagey, Table of n, a(n) for n = 1..10000

Crossrefs

For other initial terms, see A064413, A169837, A169839, A169841, A169843,A169845, A169847, A169849, A169851, A169853.

Programs

Python

from math import gcd
def aupton(terms):
    alst, aset = [12], {12}
    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
print(aupton(73)) # Michael S. Branicky, Dec 02 2021