A376199 Index where n appears in A376198.

1, 2, 3, 4, 9, 5, 10, 6, 7, 8, 11, 12, 23, 13, 14, 15, 24, 16, 25, 17, 18, 19, 26, 20, 21, 22, 27, 28, 52, 29, 53, 30, 31, 32, 33, 34, 54, 35, 36, 37, 55, 38, 56, 39, 40, 41, 57, 42, 43, 44, 45, 46, 58, 47, 48, 49, 50, 51, 59, 60, 110, 61, 62, 63, 64, 65, 111, 66, 67, 68, 112, 69, 113, 70, 71, 72, 73, 74, 114, 75, 76, 77, 115, 78, 79

Offset

1,2

Links

Michael S. Branicky, Table of n, a(n) for n = 1..100000

Prog

(Python)
from itertools import count, islice
from sympy import isprime, nextprime
def agen(): # generator of terms
    an, smc, smp, adict, n = 2, 4, 3, {1: 1, 2: 2}, 1
    for k in count(3):
        if not isprime(an):
            an = smp if an == 2*smp else smc
        else:
            an = smp if smp < smc else smc
        if an == smp: smp = nextprime(smp)
        else:
            smc += 1
            while isprime(smc): smc += 1
        if an not in adict: adict[an] = k
        while n in adict: yield adict[n]; n += 1
print(list(islice(agen(), 85))) # Michael S. Branicky, Oct 03 2024

Crossrefs

Cf. A376198, A376200-A376201, A376750-A376754.

Sequence in context: A249746 A112480 A298196 * A112095 A260435 A255554

Adjacent sequences: A376196 A376197 A376198 * A376200 A376201 A376202

Keyword

nonn

Author

N. J. A. Sloane, Oct 03 2024

Status

approved