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.

A115261 Prime numbers such that the absolute difference of the sum of their digits in odd positions and the sum of their digits in even positions is also a prime.

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%I A115261 #6 Jul 17 2014 19:57:04
%S A115261 2,3,5,7,13,29,31,41,47,53,61,79,83,97,101,113,137,139,151,157,163,
%T A115261 167,173,179,191,193,211,223,227,233,251,269,277,281,283,311,313,337,
%U A115261 359,379,383,401,409,421,431,443,467,487,541,557,563,577,599,601,607,641
%N A115261 Prime numbers such that the absolute difference of the sum of their digits in odd positions and the sum of their digits in even positions is also a prime.
%H A115261 Jens Kruse Andersen, <a href="/A115261/b115261.txt">Table of n, a(n) for n = 1..10000</a>
%e A115261 1237 is in the sequence because it is prime and abs((7+2)-(3+1)) = 5 is prime
%p A115261 Df:=proc(N) j:=1; for n from 1 while j<=N do B:= convert(ithprime(n),base,10); ap:=-(sum(B[2*i],i=1..nops(B)/2)-sum(B[2*n+1],i=0..(nops(B)-1)/2)); if (isprime(abs(ap)) = true) then a[j]:=ithprime(n); j:=j+1; fi; od; end:
%Y A115261 Cf. A040997, A005017, A063792, A087593, A042939, A041000, A040164, A115259, A115260.
%K A115261 base,nonn
%O A115261 1,1
%A A115261 _Paolo P. Lava_ and _Giorgio Balzarotti_, Jan 20 2006