A348623 a(1) = 1; for n > 1 a(n) = a(n-1) + A001227(a(n-1)).

1, 2, 3, 5, 7, 9, 12, 14, 16, 17, 19, 21, 25, 28, 30, 34, 36, 39, 43, 45, 51, 55, 59, 61, 63, 69, 73, 75, 81, 86, 88, 90, 96, 98, 101, 103, 105, 113, 115, 119, 123, 127, 129, 133, 137, 139, 141, 145, 149, 151, 153, 159, 163, 165, 173, 175, 181, 183, 187, 191, 193, 195, 203

Offset

1,2

Links

Table of n, a(n) for n=1..63.

Mathematica

NestList[# + Count[Divisors[#], _?OddQ] &, 1, 62] (* Michael De Vlieger, Oct 25 2021 *)

Prog

(PARI) f(n) = sumdiv(n, d, d%2); \\ A001227
a(n) = if (n==1, 1, my(x=a(n-1)); x + f(x)); \\ Michel Marcus, Oct 26 2021
(Python)
from math import prod
from itertools import islice
from sympy import factorint
def A348623gen(): # generator of terms
    n = 1
    yield n
    while True:
        n += prod(q+1 for p, q in factorint(n).items() if p > 2)
        yield n
A348623_list = list(islice(A348623gen(), 20)) # Chai Wah Wu, Dec 13 2021

Crossrefs

Cf. A001227, A064491.

Sequence in context: A254440 A284914 A293262 * A200049 A279984 A184017

Adjacent sequences: A348620 A348621 A348622 * A348624 A348625 A348626

Keyword

nonn

Author

Patryk Kisieniowski, Oct 25 2021

Status

approved