OFFSET
1,1
COMMENTS
Digits of a(n) can be partitioned from (least siginifacnt one) right to left into multiples of 1 to n. a(6) = 62581223 ===> 6, 25, 8, 12, 2, 3.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..200
EXAMPLE
a(3) = 1223 and a(4) = 81223 is obtained by prefixing 8 to 1223.
MATHEMATICA
nxt[{n_, a_}]:=Module[{ida=IntegerDigits[a], k=1}, While[!PrimeQ[ FromDigits[ Join[ IntegerDigits[k(n+1)], ida]]], k++]; {n+1, FromDigits[ Join[ IntegerDigits[ k(n+1)], ida]]}]; Transpose[NestList[nxt, {1, 3}, 20]][[2]] (* Harvey P. Dale, Mar 26 2015 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Sep 21 2003
EXTENSIONS
More terms from Sam Alexander, Feb 27 2004
STATUS
approved