Numerators of poly-Bernoulli numbers B_n^(k) with k=3.

Terms

a(0) =1a(1) =1a(2) =-11a(3) =-1a(4) =1243a(5) =-49a(6) =-75613a(7) =599a(8) =234671a(9) =-803a(10) =-4955857a(11) =53443a(12) =921931911863a(13) =-449291a(14) =-23461249769a(15) =1237447a(17) =-82659252107a(19) =145633840717