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A264619 a(0) = 1; for n>0, working in binary, write n followed by 1 then n-reversed (including leading zeros); show result in base 10. 4
1, 7, 21, 31, 73, 93, 107, 127, 273, 313, 341, 381, 403, 443, 471, 511, 1057, 1137, 1193, 1273, 1317, 1397, 1453, 1533, 1571, 1651, 1707, 1787, 1831, 1911, 1967, 2047, 4161, 4321, 4433, 4593, 4681, 4841, 4953, 5113, 5189, 5349, 5461, 5621, 5709, 5869, 5981, 6141, 6211, 6371, 6483, 6643, 6731, 6891, 7003, 7163, 7239 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) = A062383(n) + A264618(n);  n>0: A070939(a(n)) = 2*A070939(n)+1; A000120(a(n)) = 2*A000120(n)+1; n>0: A023416(a(n)) = 2*A023416(n). - Reinhard Zumkeller, Dec 01 2015

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 0..32767

EXAMPLE

1 -> 111 = 7,

10 -> 10101 = 21,

11 -> 11111 = 31,

100 -> 1001001 = 73,

...

MATHEMATICA

A264619[0] = 1; A264619[n_] := FromDigits[Join[#, {1}, Reverse[#]], 2]&@ IntegerDigits[n, 2] (* JungHwan Min, Dec 01 2015 *)

bnr[n_]:=Module[{idn2=IntegerDigits[n, 2]}, FromDigits[Join[idn2, {1}, Reverse[ idn2]], 2]]; Join[{1}, Array[bnr, 60]] (* Harvey P. Dale, Nov 05 2017 *)

PROG

(Haskell)

a264619 0 = 1

a264619 n = foldr (\b v -> 2 * v + b) 0 $ (reverse bs ++ (1 : bs))

            where bs = map fromIntegral $ a030308_row n

-- Reinhard Zumkeller, Dec 01 2015

CROSSREFS

Cf. A006995, A048701 (n followed by n-reversed), A264618.

First differences: A265029.

Cf. A007088, A030308, A000120, A023416, A062383, A070939.

Sequence in context: A297178 A325553 A032639 * A015729 A271972 A001485

Adjacent sequences:  A264616 A264617 A264618 * A264620 A264621 A264622

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 30 2015

STATUS

approved

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Last modified June 15 22:19 EDT 2019. Contains 324145 sequences. (Running on oeis4.)