cp's OEIS Frontend

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.

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A335409 a(n) is the least k such that A335155(n) = A335393(k).

Original entry on oeis.org

1, 3, 2, 6, 7, 4, 12, 14, 8, 5, 28, 16, 10, 13, 32, 15, 20, 26, 64, 30, 9, 52, 128, 60, 18, 25, 256, 29, 36, 50, 512, 58, 17, 100, 1024, 116, 34, 11, 2048, 57, 68, 22, 4096, 114, 33, 44, 8192, 228, 66, 21, 16384, 27, 132, 42, 32768, 54, 65, 84, 31, 108, 130
Offset: 1

Views

Author

Rémy Sigrist, Jun 06 2020

Keywords

Comments

For any n > 0, the binary representation of a(n) encodes a minimal way (in the sense of the number of operations) of obtaining A335155(n) by starting from 1 and then repeatedly adding 5 or multiplying by 3; the leading 1 corresponds to the starting value 1, and then the 0's correspond to adding 5 and the 1's correspond to multiplying by 3.

Examples

			The first terms, alongside their binary representation and A335155(n), are:
  n   a(n)  bin(a(n))  A335155(n)
  --  ----  ---------  ----------
   1     1          1   1 = 1
   2     3         11   3 = 1*3
   3     2         10   6 = 1+5
   4     6        110   8 = (1*3)+5
   5     7        111   9 = 1*3*3
   6     4        100  11 = 1+5+5
   7    12       1100  13 = (1*3)+5+5
   8    14       1110  14 = (1*3*3)+5
   9     8       1000  16 = 1+5+5+5
  10     5        101  18 = (1+5)*3
  11    28      11100  19 = (1*3*3)+5+5
  12    16      10000  21 = 1+5+5+5+5
		

Crossrefs

Programs

  • PARI
    See Links section.

Formula

A335155(n) = A335393(a(n)).

A335393 a(1) = 1 and for any n >= 1, a(2*n) = a(n) + 5, a(2*n+1) = a(n) * 3.

Original entry on oeis.org

1, 6, 3, 11, 18, 8, 9, 16, 33, 23, 54, 13, 24, 14, 27, 21, 48, 38, 99, 28, 69, 59, 162, 18, 39, 29, 72, 19, 42, 32, 81, 26, 63, 53, 144, 43, 114, 104, 297, 33, 84, 74, 207, 64, 177, 167, 486, 23, 54, 44, 117, 34, 87, 77, 216, 24, 57, 47, 126, 37, 96, 86, 243
Offset: 1

Views

Author

Rémy Sigrist, Jun 05 2020

Keywords

Comments

All terms belong to A335155.
For any k > 0, the value k appears A335392(k) times.

Examples

			a(12) = a(6) + 5 = a(3) + 5 + 5 = a(1) * 3 + 5 + 5 = 1 * 3 + 5 + 5 = 13.
		

Crossrefs

Programs

  • PARI
    a(n) = { if (n==1, 1, n%2==0, a(n\2)+5, a(n\2)*3) }

Formula

a(2^k) = 1 + 5*k for any k >= 0.
a(2^k-1) = 2^(k-1) for any k > 0.
Showing 1-2 of 2 results.