Index of 6^n within the sequence of the numbers of the form 5^i*6^j (A025622).

Terms

a(0) =1a(1) =3a(2) =6a(3) =10a(4) =15a(5) =21a(6) =28a(7) =36a(8) =45a(9) =56a(10) =68a(11) =81a(12) =95a(13) =110a(14) =126a(15) =143a(16) =161a(17) =180a(18) =201a(19) =223a(20) =246a(21) =270a(22) =295a(23) =321a(24) =348a(25) =376a(26) =405a(27) =436a(28) =468a(29) =501