A136361 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.

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

Offset: 1

Author

Alexander Adamchuk, Dec 25 2007

Keywords

• more
• nonn

Comments

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.

a(9) > (5*10^20)^(1/4). - Donovan Johnson, Jun 12 2011

Crossrefs

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

Extensions

Name corrected and a(5)-a(6) from Donovan Johnson, Nov 20 2010

a(7)-a(8) from Donovan Johnson, Jun 12 2011