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.

A095723 0+1+Prime power perfect numbers: if n=Product p_i^r_i then 01PPsigma(n)= Product {Sum p_i^r_i, 0<=s_i<=r_i, s_i is 0 or one or prime} 01PPsigma(n)=2*n.

Original entry on oeis.org

6, 28, 4512, 65520, 694400
Offset: 1

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Author

Yasutoshi Kohmoto, Jul 08 2004

Keywords

Comments

Factorizations : 2*3, 2^2*7, 2^5*3*47, 2^4*3^2*5*7*13, 2^7*5^2*7*31
No other terms < 3000000000. - Jud McCranie, Jul 16 2004

Examples

			01PPsigma(2^5*3^3)=(1+2+2^2+2^3+2^5)*(1+3+3^2+3^3)=1880
All exponents of the terms are 0 or 1 or prime.
		

Crossrefs