A319999 Filter sequence combining A173557(n) with A319993(n).

1, 2, 3, 4, 5, 6, 7, 4, 8, 9, 10, 11, 12, 13, 14, 4, 15, 16, 17, 18, 12, 19, 20, 11, 21, 22, 23, 24, 25, 26, 27, 4, 28, 29, 30, 11, 31, 32, 30, 18, 33, 22, 34, 35, 36, 37, 38, 11, 39, 40, 41, 42, 43, 44, 33, 24, 31, 45, 46, 47, 48, 49, 50, 4, 51, 52, 53, 54, 55, 56, 57, 11, 58, 59, 60, 61, 48, 56, 62, 18, 63, 64, 65, 42, 66, 67, 68, 35, 69, 70, 58, 71, 48, 72, 58, 11, 73, 74, 75, 18, 76, 77, 78, 42

Offset

1,2

Comments

Restricted growth sequence transform of ordered pair [A173557(n), A319993(n)].

For all i, j: a(i) = a(j) => A319997(i) = A319997(j).

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; };
A173557(n) = factorback(apply(p -> p-1, factor(n)[, 1]));
A319993(n) =  { my(f=factor(n)); prod(i=1, #f~, if(2==f[i, 1], -(1==f[i, 2]), (f[i, 1]^(f[i, 2]-1)))); };
v319999 = rgs_transform(vector(up_to, n, [A173557(n), A319993(n)]));
A319999(n) = v319999[n];

Crossrefs

Cf. A173557, A319993, A319997.

Cf. also A295886, A295887.

Sequence in context: A272573 A328477 A332230 * A083501 A007922 A007948

Adjacent sequences: A319996 A319997 A319998 * A320000 A320001 A320002

Keyword

nonn

Author

Antti Karttunen, Nov 08 2018

Status

approved