a(n) is the least number k such that A349474(k) = A349474(k+1) = n, or -1 if no such k exists.

Terms

a(0) =2a(1) =7a(2) =76a(3) =56a(4) =81a(5) =63a(6) =913a(7) =892a(8) =1969a(9) =4824a(10) =22855a(11) =16819a(12) =48922a(13) =170649a(14) =273216a(15) =607783a(16) =1204354a(17) =1910608a(18) =3433671a(19) =10104969a(20) =19546522a(21) =21424744a(22) =66961728a(23) =103366113a(24) =217458328a(25) =813832568a(26) =771821712a(27) =2370545332a(28) =4638470426a(29) =7190276806