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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.

A153431 a(n) is the smallest number m such that all n+1 numbers m*10^k+1 k=0,1, ...,n are prime.

Original entry on oeis.org

1, 1, 1, 4, 28, 28, 170926, 170926, 931371868, 15538734736, 89468493268, 6009549731752, 89984938946056, 43000687652274618
Offset: 0

Views

Author

Farideh Firoozbakht, Mar 15 2009, Mar 27 2009

Keywords

Comments

If n
representations of the form p*q-(p+q)where p & q are prime.
For n>3, 7 divides a(n). a(10) is greater than 4*10^10.

Examples

			28+1, 280+1, 2800+1, 28000+1, 280000+1 & 2800000+1 are prime and 28 is the smallest such number so a(5)=28.

Links

Crossrefs

Cf. A153432.

Extensions

a(11)-a(13) from Don Reble, Jul 06 2022

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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