1,1

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.

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

Adjacent sequences: A136358 A136359 A136360 this_sequence A136362 A136363 A136364

Sequence in context: A059940 A106893 A047105 this_sequence A109173 A103010 A068111

more,nonn

Alexander Adamchuk (alex(AT)kolmogorov.com), Dec 25 2007