The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A096317 a(n) is the minimal product of the smallest prime factor of each composite number in a prime gap of 2n. 1
 2, 12, 120, 1680, 10080, 221760, 2217600, 34594560, 345945600, 11762150400, 29059430400, 988020633600, 21736453939200, 225268704460800, 5999261287219200, 642466345122201600, 1367831573485977600 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(5) = 10080: 2*5 = 10. The first occurrence of a prime gap of 10 comes after 139, with the composite numbers 140,141,142,143,144,145,146,147,148 whose smallest prime factors are 2,3,2,11,2,5,2,3,2, respectively. However, their product is 15840, which is not minimal. The 6th occurrence of a prime gap of 10 comes after 409, with the composite numbers 410,411,412,413,414,415,416,417,418 having the smallest prime factors 2,3,2,7,2,5,2,3,2 respectively. Their product is 10080, which is minimal. CROSSREFS Cf. A096318. Sequence in context: A326000 A245067 A052680 * A226760 A226758 A214770 Adjacent sequences: A096314 A096315 A096316 * A096318 A096319 A096320 KEYWORD nonn AUTHOR Ray G. Opao, Aug 02 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 27 19:27 EST 2023. Contains 359846 sequences. (Running on oeis4.)