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 A342281 #10 Mar 24 2021 15:35:58 %S A342281 1,4,7,9,12,15,18,21,24,26,29,32,35,38,41,43,46,49,52,55,57,60,63,66, %T A342281 69,72,74,77,80,83,86,89,91,94,97,100,103,106,108,111,114,117,120,123, %U A342281 125,128,131,134,137,140,142,145,148,151,154,156,159,162,165,168 %N A342281 A bisection of A001951: a(n) = A001951(2*n+1). %H A342281 N. J. A. Sloane, <a href="/A115004/a115004.txt">Families of Essentially Identical Sequences</a>, Mar 24 2021 (Includes this sequence) %o A342281 (Python) %o A342281 from sympy import integer_nthroot %o A342281 def A342281(n): return integer_nthroot(8*n*(n+1)+2,2)[0] # _Chai Wah Wu_, Mar 16 2021 %Y A342281 Cf. A001951, A022842. %K A342281 nonn %O A342281 0,2 %A A342281 _N. J. A. Sloane_, Mar 16 2021 %E A342281 More terms from _Alois P. Heinz_, Mar 16 2021