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A322098 a(1)=1, a(2)=1; for n > 2, a(n) is the largest noncomposite proper divisor of the concatenation of terms a(1) through a(n-1). 1
1, 1, 1, 37, 43, 439, 31321, 3555900001, 3555900001, 3563253697383401592719, 3563253697383401592719, 2069957682701324503311258278145695430463576158940397351, 7609174114451381087553287043297264970128251910800933517241956209 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..13.

MATHEMATICA

FromDigits /@ Nest[Append[#, IntegerDigits@ Select[Divisors[FromDigits[Join @@ #]], ! CompositeQ@ # &][[-1]] ] &, {{1}, {1}, {1}}, 7] (* Michael De Vlieger, Nov 26 2018 *)

CROSSREFS

Cf. A322097.

Sequence in context: A039950 A186281 A225423 * A039351 A043174 A043954

Adjacent sequences:  A322095 A322096 A322097 * A322099 A322100 A322101

KEYWORD

nonn,base

AUTHOR

John Mason, Nov 26 2018

EXTENSIONS

a(12) corrected and a(13) added by Daniel Suteu, Jan 19 2019

STATUS

approved

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Last modified November 13 12:45 EST 2019. Contains 329094 sequences. (Running on oeis4.)