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 A004094 Powers of 2 written backwards. 28
 1, 2, 4, 8, 61, 23, 46, 821, 652, 215, 4201, 8402, 6904, 2918, 48361, 86723, 63556, 270131, 441262, 882425, 6758401, 2517902, 4034914, 8068838, 61277761, 23445533, 46880176, 827712431, 654534862, 219078635, 4281473701, 8463847412 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Freeman Dyson believes that A014963(a(n)) <> 5 is true but cannot be proved, see link. - Reinhard Zumkeller, Jan 05 2005 LINKS T. D. Noe, Table of n, a(n) for n = 0..1000 Edge Foundation, Annual Question 2005 Richard Lipton, More on testing Dyson's conjecture (2014) N. J. A. Sloane, Exciting Number Sequences (video of talk), Mar 05 2021. FORMULA a(n) = A004086(A000079(n)). - Reinhard Zumkeller, Apr 02 2014 MAPLE a:= n-> (s-> parse(cat(s[-i]\$i=1..length(s))))(""||(2^n)): seq(a(n), n=0..50); # Alois P. Heinz, Jan 21 2020 MATHEMATICA Table[FromDigits[Reverse[IntegerDigits[2^n]]], {n, 0, 35}] (* Vincenzo Librandi, Jan 22 2020 *) PROG (Haskell) a004094 = a004086 . a000079 -- Reinhard Zumkeller, Apr 02 2014 (PARI) rev(n)=subst(Polrev(digits(n)), 'x, 10) a(n)=rev(2^n) \\ Charles R Greathouse IV, Oct 20 2014 (PARI) apply( {A004094(n)=fromdigits(Vecrev(digits(2^n)))}, [0..44]) \\ M. F. Hasler, Feb 18 2021 (Magma) [Seqint(Reverse(Intseq(2^n))): n in [0..35]]; // Vincenzo Librandi, Jan 22 2020 (Python) def A004094(n): return int(str(2**n)[::-1]) # Chai Wah Wu, Feb 19 2021 CROSSREFS Cf. A014963, A102382, A102383, A102384, A102385. The following are parallel families: A000079 (2^n), A004094 (2^n reversed), A028909 (2^n sorted up), A028910 (2^n sorted down), A036447 (double and reverse), A057615 (double and sort up), A263451 (double and sort down); A000244 (3^n), A004167 (3^n reversed), A321540 (3^n sorted up), A321539 (3^n sorted down), A163632 (triple and reverse), A321542 (triple and sort up), A321541 (triple and sort down). Cf. A004086 (read n backwards). For indices of primes see A057708. Sequence in context: A206850 A094333 A018473 * A028910 A018482 A036447 Adjacent sequences: A004091 A004092 A004093 * A004095 A004096 A004097 KEYWORD nonn,base,easy AUTHOR EXTENSIONS More terms from Reinhard Zumkeller, Jan 05 2005 STATUS approved

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Last modified November 27 03:04 EST 2022. Contains 358362 sequences. (Running on oeis4.)