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A072807 n-th prime prime(n) written in base (prime(n) (mod prime(n-1))).

%I A072807 #17 Jul 03 2021 15:58:14
%S A072807 111,101,111,23,1101,101,10011,113,45,11111,101,221,101011,233,125,
%T A072807 135,111101,151,1013,1001001,211,1103,225,141,1211,1100111,1223,
%U A072807 1101101,1301,91,2003,345,10001011,149,10010111,421,431,2213,445,455,10110101
%N A072807 n-th prime prime(n) written in base (prime(n) (mod prime(n-1))).
%H A072807 Alois P. Heinz, <a href="/A072807/b072807.txt">Table of n, a(n) for n = 2..62</a> (a(63) needs digits > 9)
%e A072807 Eventually non-decimal digit symbols appear, as in case of 307=17d, in base 14 = 307 mod 293.
%p A072807 a:= proc(n) local b, p, l;
%p A072807       p:= ithprime(n); b:= irem(p, prevprime(p));
%p A072807       if b=1 then l:= 1$p
%p A072807     else l:= ""; while p>0 do l:= irem(p, b, 'p'), l od
%p A072807       fi; parse(cat(l))
%p A072807     end:
%p A072807 seq(a(n), n=2..62);  # _Alois P. Heinz_, Sep 05 2019
%t A072807 Table[BaseForm[Prime[w], Mod[Prime[w], Prime[w-1]]], {w, 2, 128}]
%t A072807 Join[{111},FromDigits[IntegerDigits[#[[2]],Mod[#[[2]],#[[1]]]]]&/@ Partition[ Prime[Range[2,50]],2,1]] (* _Harvey P. Dale_, Jul 03 2021 *)
%o A072807 (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
%Y A072807 Cf. A008713, A072803, A072804, A072805, A072806.
%K A072807 nonn,base
%O A072807 2,1
%A A072807 _Labos Elemer_, Jul 12 2002
%E A072807 Name corrected by _Michel Marcus_, Sep 05 2019