301 (number, HTTP status code, year, and other uses)

Mathematical properties

In arithmetic, 301 is a composite number and a semiprime: it equals the product of the two prime numbers 7 and 43. Its positive divisors are 1, 7, 43 and 301. It is odd, lies between 300 and 302, and is written CCI in Roman numerals. Beyond these basic facts, 301 behaves like any other ordinary integer in algebraic and number-theoretic contexts.

HTTP status: 301 Moved Permanently

One of the most widely encountered meanings of 301 is the HTTP status code "301 Moved Permanently." When a web server responds with this code it signals that the requested resource has been assigned a new permanent URL. The response normally includes a Location header giving the new address.

Common consequences and best practices:

• Clients and search engines should update stored links to the new URL.
• Search engines typically transfer search ranking signals to the target when the redirect is permanent.
• Because some user agents historically convert POST requests to GET on a 301, web developers who need to preserve the HTTP method often prefer 307 or 308 redirects.
• Avoid redirect chains and unnecessary loops to preserve performance and crawler efficiency.

Years and historical notation

The symbol 301 also denotes calendar years: 301 AD (CE) and 301 BC. These numeric labels identify wide-ranging events in different regions and eras; the meaning depends on the historical or archaeological context in which the date appears.

Other common uses and distinctions

Beyond mathematics, web protocols, and chronology, 301 appears as an identifier in other domains. For example, in the United States 301 is a well-known telephone area code used in parts of Maryland and adjacent suburbs of Washington, D.C.; that numbering plan has been overlaid by additional area codes over time to meet demand. In technical and cultural settings the three-digit token may be used as part of model numbers, product names, or room identifiers.

Notable distinctions

When dealing with web redirects, 301 should be distinguished from temporary redirect codes such as 302 and from the newer permanent codes like 308. The key distinction is permanence: 301 signals a lasting move and encourages consumers and indexers to update references, while temporary codes indicate a short-term or conditional change.