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 A254334 #24 May 22 2025 10:21:42 %S A254334 1,3,9,27,121,403,1209,3627,14921,52803,162409,491227,2273721,7225203, %T A254334 22083609,106254827,319172521,957521603,2953364809,12940502427, %U A254334 42902311321,132707334003,402122410009,2010408030027,6031224090121,18093712270403,54285137211209 %N A254334 Powers of 3 in base 60, concatenating the decimal values of the sexagesimal digits. %C A254334 Each sexagesimal digit appears as a pair of decimal digits as on a digital clock. Any leading zeros are truncated. Thus decimal 81 appears as "121" and not "0121". %H A254334 Michael De Vlieger, <a href="/A254334/b254334.txt">Table of n, a(n) for n = 0..1200</a> %F A254334 a(n) = A055643(A000244(n)). - _Michel Marcus_, Mar 02 2015 %e A254334 a(6) = 1209, since 3^6 = 729 = 12 * 60^1 + 9, thus 12:09 in clock-like notation, which becomes 1209 when restricted to numeric characters. %t A254334 f[n_] := FromDigits@ StringJoin[If[# < 10, StringJoin["0", ToString[#]], ToString[#]] & /@ IntegerDigits[3^n, 60]]; Table[f@ i, {i, 0, 26}] (* _Michael De Vlieger_, Jan 28 2015 *) %o A254334 (PARI) a(n) = subst(Pol(digits(3^n, 60)), x, 100); \\ _Michel Marcus_, Feb 22 2015 %o A254334 (Python) %o A254334 def digits(n,b=10): # list of digits of n in base b %o A254334 x, y = n, [] %o A254334 while x >= b: %o A254334 x, r = divmod(x,b) %o A254334 y.append(r) %o A254334 y.append(x) %o A254334 return list(reversed(y)) %o A254334 A254334_list = [int(''.join([format(x,'02d') for x in digits(3**i, 60)])) for i in range(10**2)] %o A254334 # _Chai Wah Wu_, Mar 14 2015 %Y A254334 Cf. A000244 (Powers of 3), A055643 (Babylonian numbers). %Y A254334 Cf. Sexagesimal representations: A250073 (Powers of 2), A254335 (Powers of 5), A254336 (Powers of 10). %K A254334 nonn,base %O A254334 0,2 %A A254334 _Michael De Vlieger_, Jan 28 2015