A113513 First number in the ascending sequence associated with A114754.
1, 10, 1, 6, 9, 3, 9, 4, 1, 30, 1, 93, 9, 39, 33, 1, 25, 22, 16, 121
Offset: 1
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.
a(4) = 76541, four successive positive integers 7,6,5,4 in descending order followed by a 1.
f:= proc(n) local k,p,j;
for k from 0 do
p:= parse(cat(seq(k+j,j=n .. 1,-1), 1));
if isprime(p) then return p fi
od
end proc:map(f, [$1..15]); # Robert Israel, Apr 03 2023
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 *)
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 *)
a(4) = 12347, four successive positive integers 1,2,3,4 in ascending order followed by a 7.
a[n_]:=(For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m, m+n-1}]);!PrimeQ[10FromDigits[v]+7], m++ ];10FromDigits[v]+7);Table[a[n], {n, 14}] - Farideh Firoozbakht
f[n_] := Block[{t = Range@n}, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {7}]; !PrimeQ@p, t++ ]; p]; Array[f, 14] (* Robert G. Wilson v *)
Table[SelectFirst[10 FromDigits[Flatten[IntegerDigits/@#]]+7&/@ Partition[ Range[1000],n,1],PrimeQ],{n,20}] (* Harvey P. Dale, Jan 29 2022 *)
a(2) = 439, two successive positive integers 4,3 in descending order followed by a 9. a(4) = 262524239 four successive positive integers 26,25,24,23 in descending order followed by a 9.
a[n_]:=If[Mod[n, 3]==0, 0, (For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m+n-1, m, -1}]);!PrimeQ[10FromDigits[v]+9], m++ ];10FromDigits[v]+9)];Table[a[n], {n, 16}] (* Farideh Firoozbakht *)
f[n_] := Block[{t = Reverse@Range@n}, If[ Mod[n, 3] == 0, 0, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {9}]; !PrimeQ@p, t++ ]; p]]; Array[f, 16] (* Robert G. Wilson v *)
a(4) = 65437, four successive positive integers 6,5,4,3 in descending order followed by a 7.
a[n_]:=(For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m+n-1, m, -1}]);!PrimeQ[10FromDigits[v]+7], m++ ];10FromDigits[v]+7);Table[a[n], {n, 14}] - Farideh Firoozbakht
f[n_] := Block[{t = Reverse@Range@n}, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {7}]; !PrimeQ@p, t++ ]; p]; Array[f, 14] (* Robert G. Wilson v *)
a(4) = 12343, four successive positive integers 1,2,3,4 in ascending order followed by a 3.
a[n_]:=If[Mod[n, 3]==0, 0, (For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m, m+n-1}]);!PrimeQ[10FromDigits[v]+3], m++ ];10FromDigits[v]+3)];Table[a[n], {n, 17}] - Farideh Firoozbakht
f[n_] := Block[{t = Range@n}, If[ Mod[n, 3] == 0, 0, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {3}]; !PrimeQ@p, t++ ]; p]]; Array[f, 20] (* Robert G. Wilson v *)
a(4) = 23459, four successive positive integers 2,3,4,5 in ascending order followed by a 9.
a[n_]:=If[Mod[n, 3]==0, 0, (For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m, m+n-1}]);!PrimeQ[10FromDigits[v]+9], m++ ];10FromDigits[v]+9)];Table[a[n], {n, 17}] - Farideh Firoozbakht
f[n_] := Block[{t = Range@n}, If[ Mod[n, 3] == 0, 0, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {9}]; !PrimeQ@p, t++ ]; p]]; Array[f, 16] (* Robert G. Wilson v *)
a(4) = 54323, four successive positive integers 5,4,3,2 in descending order followed by a 3.
a[n_]:=If[Mod[n, 3]==0, 0, (For[m=1, (v={};Do[v=Join[v, IntegerDigits[k]], {k, m+n-1, m, -1}]);!PrimeQ[10FromDigits[v]+3], m++ ];10FromDigits[v] +3)];Table[a[n], {n, 17}] - Farideh Firoozbakht
f[n_] := Block[{t = Reverse@Range@n}, If[Mod[n, 3] == 0, 0, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {3}]; ! PrimeQ@p, t++ ]; p]]; Array[f, 18] (* Robert G. Wilson v *)
a(2) = 3 as 11_2 is prime. a(3) = 5 as 12_3 is prime. a(4) = 109 as 1231_4 is prime. a(5) = 7 as 12_5 is prime. a(6) = 18796638871 as 12345101112131_6 is prime. a(7) = 131870666077 as 12345610111213_7 is prime. a(8) = 83 as 123_8 is prime. a(9) = 11 as 12_9 is prime. a(10) = 1234567891 as 1234567891_10 is prime. See A176942. a(11) = 13 as 12_11 is prime. a(12) = 24677 as 12345_12 is prime.
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