A163682 - OEIS

%I #9 Sep 08 2022 08:45:47

%S 2030789,2542237,3863017,4508341,7001123,7583341,8482459,8547677,

%T 8916239,9194677,9470017,11117123,11755673,11999563,13691563,13898237,

%U 15906127,16047673,16272343,16299013,16829563,17437457,17604347

%N Smaller prime p in Ormiston pairs (p, q) with q - p = 90.

%C An Ormiston pair (or rearrangement prime pair) is a pair of consecutive primes that use the same digits in a different order.

%H G. C. Greubel, <a href="/A163682/b163682.txt">Table of n, a(n) for n = 1..5000</a>

%H Jens Kruse Andersen, <a href="http://primerecords.dk/ormiston_tuples.htm">Ormiston Tuples</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RearrangementPrimePair.html">Rearrangement Prime Pair</a>

%e (3863017, 3863107) is an Ormiston pair with gap 90, so 3863017 is in the sequence.

%t Transpose[Select[Select[Partition[Prime[Range[70000]], 2, 1], Last[#] - First[#] == 90 &], Sort[IntegerDigits[First[#]]] == Sort[IntegerDigits[Last[#]]] &]][[1]] (* _G. C. Greubel_, Aug 02 2017 *)

%o (Magma) [ p: p in PrimesUpTo(17700000) | q-p eq 90 and a eq b where a is Sort(Intseq(p)) where b is Sort(Intseq(q)) where q is NextPrime(p) ];

%Y Subsequence of A069567.

%Y Cf. A072274, A163863.

%K nonn,base

%O 1,1

%A _Klaus Brockhaus_, Aug 03 2009

%E Keyword base added by _Klaus Brockhaus_, Sep 18 2009