A292266 - OEIS

%I #10 Oct 04 2017 14:04:55

%S 1,2,3,4,5,6,7,8,9,10,5,11,12,10,13,14,15,16,17,16,18,19,16,20,21,22,

%T 23,24,25,26,27,28,29,30,31,32,33,24,34,35,36,37,38,39,11,16,6,40,41,

%U 42,43,44,7,45,46,47,48,49,50,51,52,53,43,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,57,76,77,78,79,80,81

%N Restricted growth sequence transform of A292265; a filter related to Shevelev's algorithm for computing A002326.

%C For all i, j: a(i) = a(j) => A002326(i) = A002326(j).

%H Antti Karttunen, <a href="/A292266/b292266.txt">Table of n, a(n) for n = 0..32768</a>

%o (PARI)

%o allocatemem(2^30);

%o rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };

%o write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }

%o A000265(n) = (n >> valuation(n, 2));

%o A019565(n) = {my(j,v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ This function from _M. F. Hasler_

%o A292265(n) = { my(x = n+n+1, z = A019565(valuation(1+x,2)), m = A000265(1+x)); while(m!=1, z *= A019565(valuation(x+m,2)); m = A000265(x+m)); z; };

%o write_to_bfile(0,rgs_transform(vector(32769,n,A292265(n-1))),"b292266_upto32768.txt");

%Y Cf. A002326, A292239, A292265.

%K nonn

%O 0,2

%A _Antti Karttunen_, Oct 02 2017