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.

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A073861 Smaller of pair of successive n-digit primes with maximal difference.

Original entry on oeis.org

3, 89, 887, 9551, 31397, 492113, 4652353, 47326693, 436273009, 4302407359, 42652618343, 738832927927, 7177162611713, 90874329411493, 218209405436543, 1693182318746371, 80873624627234849, 804212830686677669
Offset: 1

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Author

Amarnath Murthy, Aug 15 2002

Keywords

Comments

A subsequence of A002386 (assuming that there is an n-digit term in A002386 for all values of n). - M. F. Hasler, Apr 28 2014

Examples

			a(3) = 887, the next prime is 907, 907-887=20 is the maximal possible difference of two 3-digit primes and no smaller pair exhibits this property.
		

Programs

  • Mathematica
    Table[Last[Sort[{#[[2]]-#[[1]],#[[1]],#[[2]]}&/@Partition[Prime[Range[PrimePi[10^i]+1,PrimePi[10^(i+1)]]],2,1]]][[2]],{i,7}] (* Harvey P. Dale, Jan 23 2010 *)

Formula

A073861 = A000040 o A241623. - M. F. Hasler, Apr 28 2014
a(n) = max { p in A002386 | nextprime(p) < 10^n } (under the assumption given in the comment). - M. F. Hasler, Apr 28 2014

Extensions

Corrected error and added terms Harvey P. Dale, Jan 23 2010
a(9)-a(18) from Donovan Johnson, Nov 29 2010
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