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A072807 n-th prime prime(n) written in base (prime(n) (mod prime(n-1))). 5
111, 101, 111, 23, 1101, 101, 10011, 113, 45, 11111, 101, 221, 101011, 233, 125, 135, 111101, 151, 1013, 1001001, 211, 1103, 225, 141, 1211, 1100111, 1223, 1101101, 1301, 91, 2003, 345, 10001011, 149, 10010111, 421, 431, 2213, 445, 455, 10110101 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 2..62 (a(63) needs digits > 9)

EXAMPLE

Eventually non-decimal digit symbols appear, as in case of 307=17d, in base 14 = 307 mod 293.

MAPLE

a:= proc(n) local b, p, l;

      p:= ithprime(n); b:= irem(p, prevprime(p));

      if b=1 then l:= 1$p

    else l:= ""; while p>0 do l:= irem(p, b, 'p'), l od

      fi; parse(cat(l))

    end:

seq(a(n), n=2..62);  # Alois P. Heinz, Sep 05 2019

MATHEMATICA

Table[BaseForm[Prime[w], Mod[Prime[w], Prime[w-1]]], {w, 2, 128}]

PROG

(PARI) a(n) = {my(p=prime(n), q=prime(n-1)); if ((p % q) != 1, d=digits(p, p % q); if (#select(x->(x>9), d), 0, fromdigits(d, 10)), fromdigits(vector(p, k, 1), 10)); } \\ Michel Marcus, Sep 05 2019

CROSSREFS

Cf. A008713, A072803, A072804, A072805, A072806.

Sequence in context: A282652 A282796 A282800 * A282976 A284083 A252724

Adjacent sequences:  A072804 A072805 A072806 * A072808 A072809 A072810

KEYWORD

nonn,base

AUTHOR

Labos Elemer, Jul 12 2002

EXTENSIONS

Name corrected by Michel Marcus, Sep 05 2019

STATUS

approved

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Last modified February 23 07:28 EST 2020. Contains 332159 sequences. (Running on oeis4.)