A349806 a(n) = A099610(n) - n^2.

14, 11, 6, 5, 8, 3, 2, 1, 4, 11, 2, 1, 8, 5, 10, 3, 2, 3, 4, 3, 4, 1, 4, 3, 4, 3, 2, 1, 2, 1, 4, 3, 10, 1, 2, 3, 2, 13, 6, 3, 4, 1, 2, 1, 6, 1, 6, 1, 6, 1, 2, 1, 2, 5, 2, 3, 12, 1, 6, 1, 16, 1, 4, 1, 2, 3, 8, 3, 2, 7, 4, 7, 2, 9, 2, 1, 4, 1, 2, 1, 22, 5, 2, 5, 6, 1, 2, 1, 18, 5, 4, 1, 2, 7, 6, 1, 2, 3, 8, 1, 6, 1, 8, 1, 4, 1, 4, 1, 4, 15, 12, 13, 4

Offset

1,1

Comments

a(n) > 0 follows from the definition of A099610.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Module[{nn=120, p2p}, p2p=Union[Times@@@Subsets[Prime[Range[2, PrimePi[ Ceiling[ nn^2/3]]]], {2}]]; Table[SelectFirst[p2p, #>n^2&]-n^2, {n, nn}]] (* Harvey P. Dale, Dec 06 2021 *)

Prog

(Python)
from itertools import count
from sympy import factorint
def A349806(n):
    for i in count(n**2+(n%2)+1, 2):
        fs = factorint(i)
        if len(fs) == 2 == sum(fs.values()):
            return i-n**2 # Chai Wah Wu, Dec 05 2021

Crossrefs

Cf. A099610.

Sequence in context: A147370 A140739 A305946 * A259531 A240815 A305938

Adjacent sequences: A349803 A349804 A349805 * A349807 A349808 A349809

Keyword

nonn

Author

N. J. A. Sloane, Dec 05 2021

Status

approved