A030623 Powers of 2 grouped in pairs of 2 digits (version 2).

12, 48, 16, 32, 64, 12, 82, 56, 51, 21, 2, 42, 4, 84, 9, 68, 19, 21, 63, 84, 32, 76, 86, 55, 36, 13, 10, 72, 26, 21, 44, 52, 42, 88, 10, 48, 57, 62, 9, 71, 52, 41, 94, 30, 48, 38, 86, 8, 16, 77, 72, 16, 33, 55, 44, 32, 67, 10, 88, 64, 13, 42, 17, 72, 82, 68, 43, 54, 56, 53, 68

Offset

1,1

Comments

When a 0 occurs as the most significant digit of the pair, it is simply ignored, e.g., "02" becomes just 2. The following pairs are unaffected. - Alonso del Arte, Mar 28 2020

Links

Table of n, a(n) for n=1..71.

Example

The first few powers of 2 are 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192. The digits are 1, 2, 4, 8, 1, 6, 3, 2, 6, 4, 1, 2, 8, 2, 5, 6, 5, 1, 2, 1,0, 2, 4, 2, 0, 4, 8, 4, 0, 9, 6. Grouping them in pairs, we obtain 12, 48, 16, 32, 64, 12, 82, 56, 51, 21, 02, 42, 04, 84, 09, 68, etc.

Maple

sq:=[]: for n from 0 to 100 do s:=convert(2^n, base, 10): l:=nops(s): sq:=[op(sq), seq(s[l-i], i=0..l-1)] od: seq(sq[2*i-1]*10+sq[2*i], i=1..100); # C. Ronaldo

Mathematica

FromDigits/@Partition[Flatten[IntegerDigits[2^Range[0, 63]]], 2] (* Alonso del Arte, Mar 28 2020 *)

Prog

(Scala) (List.fill(63)(2: BigInt)).scanLeft(1: BigInt)(_ * _).map(_.toString.toCharArray).flatten.sliding(2, 2).map(_.toArray).toList.map(new String(_)).map(Integer.parseInt(_)) // Alonso del Arte, Mar 28 2020

Crossrefs

Cf. A030622, A030624, A000079, A000455.

Sequence in context: A244803 A024183 A051673 * A030624 A002612 A124351

Adjacent sequences: A030620 A030621 A030622 * A030624 A030625 A030626

Keyword

nonn,base,easy

Author

Alexei Kozlowski (bros(AT)spf.minsk.by)

Extensions

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 03 2005

Status

approved