cp's OEIS Frontend

A253550 Shift one instance of the largest prime one step towards larger primes: a(1) = 1, for n>1: a(n) = (n / prime(g)) * prime(g+1), where g = A061395(n), index of the greatest prime dividing n.

%I A253550 #11 Jan 15 2015 11:39:29
%S A253550 1,3,5,6,7,10,11,12,15,14,13,20,17,22,21,24,19,30,23,28,33,26,29,40,
%T A253550 35,34,45,44,31,42,37,48,39,38,55,60,41,46,51,56,43,66,47,52,63,58,53,
%U A253550 80,77,70,57,68,59,90,65,88,69,62,61,84,67,74,99,96,85,78,71,76,87,110,73,120,79,82,105,92,91,102,83,112,135,86,89
%N A253550 Shift one instance of the largest prime one step towards larger primes: a(1) = 1, for n>1: a(n) = (n / prime(g)) * prime(g+1), where g = A061395(n), index of the greatest prime dividing n.
%H A253550 Antti Karttunen, <a href="/A253550/b253550.txt">Table of n, a(n) for n = 1..10000</a>
%F A253550 a(1) = 1; for n>1: a(n) = A065091(A061395(n)) * A052126(n).
%F A253550 Other identities. For all n >= 1:
%F A253550 A252462(a(n)) = n. [A252462 works as an inverse function for this injection.]
%F A253550 a(n) <= A253560(n).
%o A253550 (Scheme) (define (A253550 n) (if (= 1 n) n (* (A065091 (A061395 n)) (A052126 n))))
%Y A253550 Inverse: A252462.
%Y A253550 Cf. A102750 (same terms, but with 2 instead of 1, sorted into ascending order).
%Y A253550 Cf. A003961, A052126, A065091, A061395, A122111, A253553, A253554, A253560, A253563, A253565.
%K A253550 nonn
%O A253550 1,2
%A A253550 _Antti Karttunen_, Jan 03 2015