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 A008568 #28 Mar 23 2025 03:56:32 %S A008568 1,7,4,9,3,4,3,2,4,0,1,1,6,8,0,7,1,1,7,6,4,9,8,2,3,5,4,3,5,7,6,4,8,0, %T A008568 1,4,0,3,5,3,6,0,7,2,8,2,4,7,5,2,4,9,1,9,7,7,3,2,6,7,4,3,1,3,8,4,1,2, %U A008568 8,7,2,0,1,9,6,8,8,9,0,1,0,4,0,7,6,7,8,2,2,3,0,7,2,8,4,9,4,7,4 %N A008568 Digits of powers of 7. %C A008568 Irregular table with row length sequence A210062. - _Jason Kimberley_, Nov 26 2012 %C A008568 The constant whose decimal expansion is this sequence is irrational (Mahler, 1981). - _Amiram Eldar_, Mar 23 2025 %H A008568 Seiichi Manyama, <a href="/A008568/b008568.txt">Rows n = 0..100, flattened</a> %H A008568 Kurt Mahler, <a href="https://doi.org/10.1016/0022-314X(81)90010-X">On some irrational decimal fractions</a>, Journal of Number Theory, Vol. 13, No. 2 (1981), pp. 268-269. %e A008568 Triangle begins: %e A008568 1; %e A008568 7; %e A008568 4, 9; %e A008568 3, 4, 3; %e A008568 2, 4, 0, 1; %e A008568 1, 6, 8, 0, 7; %e A008568 1, 1, 7, 6, 4, 9; %e A008568 8, 2, 3, 5, 4, 3; %e A008568 ... %t A008568 Flatten[IntegerDigits[7^Range[0,20]]] (* _Harvey P. Dale_, Mar 03 2011 *) %Y A008568 Cf. A000420, A210062. %Y A008568 Cf. A000455, A008564, A008565, A008566, A008567, A008569, A008570, A008571, A008572, A008573, A010054. %K A008568 nonn,base,easy,tabf %O A008568 0,2 %A A008568 _N. J. A. Sloane_