A261269 -id:A261269

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A261270

Base-10 representation of A261269.

+20
3

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

MATHEMATICA

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 *)

CROSSREFS

Cf. A261269.

KEYWORD

nonn,easy,base

AUTHOR

Clark Kimberling, Sep 17 2015

STATUS

approved

A048553

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

+10
10

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

LINKS

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

MAPLE

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

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

MATHEMATICA

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 *)

CROSSREFS

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

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, May 15 1999

STATUS

approved

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