A136361 - OEIS

%I #15 Sep 16 2018 16:37:41

%S 3,5,31,132,1068,9672,50664,145060

%N Square roots of the perfect squares in A136360; or numbers k such that k^4 is in A133459 = the sums of two nonzero pentagonal pyramidal numbers.

%C Corresponding perfect squares in A136360 are a(n)^2 = {9, 25, 961, 17424, ...}. They correspond to the perfect fourth powers in A133459 = Sums of two nonzero pentagonal pyramidal numbers. a(n)^4 are the terms of A133459: {81, 525, 923521, 303595776, ...}. Note that the first three terms are prime.

%C a(9) > (5*10^20)^(1/4). - _Donovan Johnson_, Jun 12 2011

%Y Cf. A136359, A136360, A133459, A002311, A002411, A053721.

%K more,nonn

%O 1,1

%A _Alexander Adamchuk_, Dec 25 2007

%E Name corrected and a(5)-a(6) from _Donovan Johnson_, Nov 20 2010

%E a(7)-a(8) from _Donovan Johnson_, Jun 12 2011