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.

A114758 Smallest prime of the form: n successive positive integers in descending order followed by a 1.

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%I A114758 #15 Apr 03 2023 14:34:41
%S A114758 11,211,5431,76541,17161514131,1211109871,98765431,876543211,
%T A114758 9876543211,242322212019181716151,11109876543211,
%U A114758 1131121111101091081071061051041031021,555453525150494847464544431
%N A114758 Smallest prime of the form: n successive positive integers in descending order followed by a 1.
%H A114758 Robert Israel, <a href="/A114758/b114758.txt">Table of n, a(n) for n = 1..173</a>
%e A114758 a(4) = 76541, four successive positive integers 7,6,5,4 in descending order followed by a 1.
%p A114758 f:= proc(n) local k,p,j;
%p A114758   for k from 0 do
%p A114758     p:= parse(cat(seq(k+j,j=n .. 1,-1), 1));
%p A114758     if isprime(p) then return p fi
%p A114758   od
%p A114758 end proc:map(f, [$1..15]); # _Robert Israel_, Apr 03 2023
%t A114758 a[n_]:=(For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m+n-1, m, -1}]);!PrimeQ[10FromDigits[v]+1], m++ ];10FromDigits[v]+1);Table[a[n], {n, 14}] (* _Farideh Firoozbakht_, Jan 02 2006 *)
%t A114758 f[n_] := Block[{t = Reverse@Range@n}, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {1}]; ! PrimeQ@p, t++ ]; p]; Array[f, 13] (* _Robert G. Wilson v_, Jan 03 2006 *)
%Y A114758 Cf. A113514, A114754, A114755, A114756, A114757, A114759, A112716, A108145, A114761.
%K A114758 base,nonn
%O A114758 1,1
%A A114758 _Amarnath Murthy_, Jan 01 2006
%E A114758 Extended by _Robert G. Wilson v_, _Ray Chandler_ and _Farideh Firoozbakht_, Jan 02 2006
%E A114758 More terms from _Robert G. Wilson v_, Jan 03 2006