a(n) = greatest k such that s(j) > 0 for all j < k at end of stage n in forming A026409.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =7a(5) =10a(6) =12a(7) =15a(8) =19a(9) =23a(10) =28a(11) =31a(12) =36a(13) =37a(14) =45a(15) =49a(16) =58a(17) =60a(18) =67a(19) =75a(20) =77a(21) =90a(22) =91a(23) =104a(24) =110a(25) =111a(26) =125a(27) =135a(28) =145a(29) =158