A318881 Restricted growth sequence transform of A277906, the least number with same prime signature as phi(n).

1, 1, 2, 2, 3, 2, 4, 3, 4, 3, 4, 3, 5, 4, 6, 6, 7, 4, 5, 6, 5, 4, 4, 6, 5, 5, 5, 5, 5, 6, 8, 7, 5, 7, 9, 5, 10, 5, 9, 7, 9, 5, 8, 5, 9, 4, 4, 7, 8, 5, 11, 9, 5, 5, 9, 9, 10, 5, 4, 7, 12, 8, 10, 11, 13, 5, 8, 11, 5, 9, 8, 9, 14, 10, 9, 10, 12, 9, 8, 11, 9, 9, 4, 9, 15, 8, 9, 9, 9, 9, 14, 5, 12, 4, 14, 11, 16, 8, 12, 9, 10, 11, 8, 13, 13

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Prog

(PARI)
up_to = 65537;
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; };
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
A277906(n) = A046523(eulerphi(n));
v318881 = rgs_transform(vector(up_to, n, A277906(n)));
A318881(n) = v318881[n];

Crossrefs

Cf. A000010, A046523, A277906, A319342, A319343, A319344, A319345.

Sequence in context: A323164 A363685 A339666 * A280338 A339147 A062821

Adjacent sequences: A318878 A318879 A318880 * A318882 A318883 A318884

Keyword

nonn

Author

Antti Karttunen, Sep 17 2018

Status

approved