Sequence formed by reading rows of triangle defined in A011971.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =7a(5) =10a(6) =15a(7) =20a(8) =27a(9) =37a(10) =52a(11) =67a(12) =87a(13) =114a(14) =151a(15) =203a(16) =255a(17) =322a(18) =409a(19) =523a(20) =674a(21) =877a(22) =1080a(23) =1335a(24) =1657a(25) =2066a(26) =2589a(27) =3263a(28) =4140a(29) =5017