This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A382148 #7 Mar 18 2025 15:46:37
%S A382148 0,14,1,3,79,11,30,8,108,17,6,111,169,18,76,78,74,388,239,86,383,345,
%T A382148 191,1017,178,486,163,1828,209,364,484,582,160,289,436,878,174,320,37,
%U A382148 1029,698,1386,768,618,558,212,1318,2213,826,350,877,1780,1033,407,188,229,1478,467,305
%N A382148 Index of first occurrence of n in A381238, or -1 if n does not appear there.
%t A382148 b[n_] := b[n] = Sec[b[n-1]]^2; b[0] = 1; With[{v = Floor[Array[b, 600, 0]]}, -1 + TakeWhile[FirstPosition[v, #] & /@ Range[Max[v]], ! MissingQ[#] &] // Flatten] (* _Amiram Eldar_, Mar 18 2025 *)
%Y A382148 Cf. A381238.
%K A382148 nonn
%O A382148 1,2
%A A382148 _N. J. A. Sloane_, Mar 17 2025
%E A382148 More terms from _Amiram Eldar_, Mar 18 2025