A293892 Restricted growth sequence transform of A083722.

1, 1, 1, 2, 1, 3, 1, 4, 5, 6, 1, 7, 1, 8, 9, 10, 1, 11, 1, 12, 13, 14, 1, 15, 16, 17, 15, 18, 1, 19, 1, 20, 21, 22, 23, 24, 1, 25, 26, 27, 1, 28, 1, 29, 30, 31, 1, 32, 33, 34, 35, 36, 1, 37, 38, 39, 40, 41, 1, 42, 1, 43, 44, 45, 46, 47, 1, 48, 49, 50, 1, 51, 1, 52, 53, 54, 55, 56, 1, 57, 58, 59, 1, 60, 61, 62, 63, 64, 1, 65, 66, 67, 68, 69, 70, 71, 1, 72, 73

Offset: 1

Author

Antti Karttunen, Nov 02 2017

Keywords

• nonn

Comments

a(n) = 1 iff n is prime or n is 1.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65536

Crossrefs

Cf. A083722, A293893, A293894.

Programs

PARI

allocatemem(2^30);
up_to = 65536;
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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A083722(n) = { if(n==1, return (1)); my(gpf = vecmax(factor(n)[, 1])); my(pp = 1); forprime(p=gpf+1, n, pp *= p; ); pp; } \\ This function from Michel Marcus, Jun 26 2016
write_to_bfile(1,rgs_transform(vector(up_to,n,A083722(n))),"b293892.txt");