A318500 Filter sequence combining A305897 and the parity of n.

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

Offset

1,2

Comments

Restricted growth sequence transform of ordered pair [A000035(n), A246277(n)], or equally, of ordered pair [A007814(n), A246277(n)].

For all i, j:

A305801(i) = A305801(j) => a(i) = a(j) => A305891(i) = A305891(j) => A291761(i) = A291761(j).

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Prog

(PARI)
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; };
A246277(n) = if(1==n, 0, my(f = factor(n), k = primepi(f[1, 1])-1); for (i=1, #f~, f[i, 1] = prime(primepi(f[i, 1])-k)); factorback(f)/2);
v318500 = rgs_transform(vector(up_to, n, [(n%2), A246277(n)]));
A318500(n) = v318500[n];

Crossrefs

Cf. A246277, A291761, A305801, A305891, A305897.

Sequence in context: A322314 A322022 A352898 * A325384 A353522 A323371

Adjacent sequences: A318497 A318498 A318499 * A318501 A318502 A318503

Keyword

nonn

Author

Antti Karttunen, Sep 24 2018

Status

approved