This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A132106 #24 Jan 06 2025 10:00:17
%S A132106 1,3,5,7,11,13,17,19,23,27,31,33,39,41,45,49,55,57,63,65,71,75,79,81,
%T A132106 89,93,97,101,107,109,117,119,125,129,133,137,147,149,153,157,165,167,
%U A132106 175,177,183,189,193,195,205,209,215,219,225,227,235,239,247,251,255,257,269
%N A132106 a(n) = 1 + floor(sqrt(n)) + Sum_{i=1..n} floor(n/i).
%C A132106 Matches first 8 odd primes.
%H A132106 Antti Karttunen, <a href="/A132106/b132106.txt">Table of n, a(n) for n = 0..16384</a>
%H A132106 Aidan Botkin, Madeline L. Dawsey, David J. Hemmer, Matthew R. Just, and Robert Schneider, <a href="https://www.arxiv.org/abs/2501.00580">Partition-theoretic model of prime distribution</a>, arXiv:2501.00580 [math.NT], 2024. See page 6.
%F A132106 a(n) = 1 + Sum_{i=1..n} A161841(i) for n > 0. - _Christian Krause_, Jun 17 2021
%F A132106 a(n) = 1 + A000196(n) + A006218(n). - _Vaclav Kotesovec_, Jul 01 2021
%t A132106 a[n_]:=1+2Sum[Ceiling[DivisorSigma[0,k]/2],{k,n-1}]; Array[a,61] (* _Stefano Spezia_, Jan 06 2025 *)
%o A132106 (PARI) a(n) = 1 + sqrtint(n) + sum(i=1, n, n\i); \\ _Michel Marcus_, Jun 17 2021
%o A132106 (Python)
%o A132106 from math import isqrt
%o A132106 def A132106(n): return (lambda m: 2*(sum(n//k for k in range(1, m+1)))+m*(1-m)+1)(isqrt(n)) # _Chai Wah Wu_, Oct 08 2021
%Y A132106 Cf. A000196, A006218, A161841 (first differences).
%K A132106 nonn
%O A132106 0,2
%A A132106 Richard C. Schroeppel, Oct 31 2007