A261269 -id:A261269 - cp's OEIS frontend

A261270 Base-10 representation of A261269.

3, 7, 29, 59, 239, 479, 3833, 30671, 61343, 981493, 3925973, 62815573, 502524587, 2010098351, 16080786809, 1029170355779, 4116681423119, 65866902769909, 263467611079637, 2107740888637103, 134895416872774619, 17266613359715151259, 1105063255021769680613

Offset: 1

Clark Kimberling, Sep 17 2015

Clark Kimberling, Table of n, a(n) for n = 1..500

Cf. A261269.

b = 2; s = {{1}}; Do[NestWhile[# + 1 &, 0, ! (PrimeQ[FromDigits[tmp = Join[Last[s],(nn = #; IntegerDigits[nn - Sum[b^n, {n, l = NestWhile[# + 1 &, 1, ! (nn - (Sum[b^n, {n, #}]) < 0) &] - 1}], b, l + 1])], b]]) &]; AppendTo[s, tmp], {30}]; Map[FromDigits, s]; Map[FromDigits, s] (* A261200 *)
Map[FromDigits[#, b] &, s] (* A261201 *)
(* Peter J. C. Moses, Aug 06 2015 *)

A048553 a(n+1) is next smallest prime beginning with a(n), initial prime is 11.

Original entry on oeis.org

11, 113, 11311, 113111, 1131113, 11311133, 1131113353, 113111335313, 11311133531339, 113111335313399, 1131113353133993, 113111335313399321, 11311133531339932153, 1131113353133993215379, 113111335313399321537911

Offset: 0

Patrick De Geest, May 15 1999

Clark Kimberling, Table of n, a(n) for n = 0..498

Cf. A048549-A048556, A261199-A261201, A261269-A261270.

f:= proc(n)
  local p, d;
  for d from 1 do
    p:= nextprime(n*10^d);
    if p < (n+1)*10^d then return p fi
  od
end proc:
A[1]:= 11:
for n from 2 to 20 do A[n]:= f(A[n-1]) od:
seq(A[n], n=1..20); # Robert Israel, Aug 16 2015

a = {11}; Do[k = 1; w = IntegerDigits[a[[n - 1]]];
While[CompositeQ@ FromDigits[Join[w, IntegerDigits@ k]], k += 2];
AppendTo[a, FromDigits[Join[w, IntegerDigits@ k]]], {n, 2, 15}]; a (* Michael De Vlieger, Sep 21 2015 *)

cp's OEIS Frontend

A261270 Base-10 representation of A261269.

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