login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Least number with the same prime signature as {the n-th quarter-square}+1.
3

%I #8 Nov 22 2016 21:50:42

%S 1,2,2,2,2,6,2,2,6,6,2,2,2,12,6,6,2,6,6,2,6,6,6,6,2,30,6,2,2,6,2,2,30,

%T 30,2,12,8,6,6,2,2,30,2,6,12,30,6,2,2,6,30,2,6,30,2,6,6,6,6,6,12,30,6,

%U 12,6,30,2,6,6,6,6,2,6,30,30,12,2,6,6,2,6,12,2,6,6,60,6,6,6,6,6,6,30,210,6,6,6,6,30,6,2,6,6,6,6,30,6,2,2,30,30,2,6

%N Least number with the same prime signature as {the n-th quarter-square}+1.

%C Great majority of the terms seem to be primorials (A002110), 9149 of the first 10000, meaning also that the corresponding terms in A033638 are squarefree (A005117).

%H Antti Karttunen, <a href="/A278260/b278260.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A046523(A033638(n)).

%o (Scheme) (define (A278260 n) (A046523 (A033638 n)))

%Y Cf. A002110, A005117, A033638, A046523.

%Y Cf. A278162 (bisection).

%Y Cf. also A278254, A278259.

%K nonn

%O 1,2

%A _Antti Karttunen_, Nov 22 2016