cp's OEIS Frontend

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.

A328112 a(1) = 0, for primes p, a(p) = 1, and for any other number n, a(n) = max(A003415(n), A276086(n)).

Original entry on oeis.org

0, 1, 1, 9, 1, 5, 1, 15, 30, 45, 1, 25, 1, 75, 150, 225, 1, 125, 1, 375, 750, 1125, 1, 625, 1250, 1875, 3750, 5625, 1, 31, 1, 80, 42, 63, 126, 60, 1, 105, 210, 315, 1, 175, 1, 525, 1050, 1575, 1, 875, 1750, 2625, 5250, 7875, 1, 4375, 8750, 13125, 26250, 39375, 1, 92, 1, 147, 294, 441, 882, 245, 1, 735, 1470, 2205, 1, 1225, 1, 3675, 7350, 11025, 22050
Offset: 1

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Author

Antti Karttunen, Oct 07 2019

Keywords

Comments

Apart from primes p, for which a(p) = 1, the only duplicated values among the first 65537 terms are a(30040) = a(32344) = 51108 and a(30150) = a(60278) = 47685.

Examples

			As 30150 is not a prime, a(30150) = max(A003415(30150), A276086(30150)) = max(47685, 40817) = 47685.
As 60278 is not a prime, a(60278) = max(A003415(60278), A276086(60278)) = max(30141, 47685) = 47685.
		

Crossrefs

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A276086(n) = { my(i=0,m=1,pr=1,nextpr); while((n>0),i=i+1; nextpr = prime(i)*pr; if((n%nextpr),m*=(prime(i)^((n%nextpr)/pr));n-=(n%nextpr));pr=nextpr); m; };
    A328112(n) = if(1==n,0,if(isprime(n),1,max(A003415(n),A276086(n))));