cp's OEIS Frontend

A257475 Position of second and last occurrence of n in A256918.

%I A257475 #12 Oct 23 2024 20:27:56
%S A257475 2,6,9,12,8,14,30,17,20,28,123,23,201,32,25,39,300,46,825,43,34,125,
%T A257475 946,51,27,203,47,52,3094,56,7060,62,127,302,54,71,13528,827,205,61,
%U A257475 28659,79,40811,132,58,948,46658,65,81,99,304,210,57450,69,134,77,829
%N A257475 Position of second and last occurrence of n in A256918.
%C A257475 GCD(A257218(a(n)),A257218(a(n)-1)) = n;
%C A257475 a(n) > A257120(n); a(n) = A257120 + A257478(n).
%H A257475 Hiroaki Yamanouchi, <a href="/A257475/b257475.txt">Table of n, a(n) for n = 1..72</a>
%e A257475 Cf. A257478.
%o A257475 (Haskell)
%o A257475 a257475 n = f 1 a256918_list where
%o A257475    f i (u:us) = (if u == n then g else f) (i + 1) us
%o A257475    g j (v:vs) =  if v == n then j else g  (j + 1) vs
%Y A257475 Cf. A256918, A257120, A257478, A257218.
%K A257475 nonn
%O A257475 1,1
%A A257475 _Reinhard Zumkeller_, Apr 25 2015
%E A257475 a(38)-a(57) from _Hiroaki Yamanouchi_, May 03 2015