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.

Showing 1-9 of 9 results.

A231724 a(n) = the difference between the n-th node of the infinite trunk of the factorial beanstalk (A219666(n)) and the greatest integer (A219655(n)) which is as many A219651-iteration steps distanced from the root (zero); a(n) = A219655(n) - A219666(n).

Original entry on oeis.org

0, 0, 1, 0, 0, 1, 3, 2, 0, 0, 1, 3, 2, 1, 1, 3, 3, 2, 2, 1, 3, 4, 4, 3, 4, 5, 6, 0, 0, 1, 3, 2, 1, 1, 3, 3, 2, 2, 1, 3, 4, 4, 3, 4, 5, 7, 4, 4, 5, 1, 3, 3, 2, 2, 1, 3, 4, 4, 3, 4, 5, 7, 5, 7, 7, 5, 6, 6, 1, 3, 4, 4, 3, 4, 5, 7, 5, 7, 7, 5, 6, 6, 2, 2, 3, 4, 5
Offset: 0

Views

Author

Antti Karttunen, Nov 13 2013

Keywords

Comments

For all n, the following holds: A219653(n) <= A219666(n) <= A219655(n). This sequence gives the distance of the node n in the infinite trunk of factorial beanstalk (A219666(n)) from the right (greater) edge of the A219654(n) wide window which it at that point must pass through.
This sequence relates to the factorial base representation (A007623) in the same way as A218604 relates to the binary system and similar remarks apply here.

Crossrefs

Programs

Formula

a(n) = A219655(n) - A219666(n).
A219654(n) = a(n) + A231723(n) + 1.

A219666 The infinite trunk of factorial expansion beanstalk. The only infinite sequence such that a(n-1) = a(n) - sum of digits in factorial expansion of a(n).

Original entry on oeis.org

0, 1, 2, 5, 7, 10, 12, 17, 23, 25, 28, 30, 35, 40, 46, 48, 52, 57, 63, 70, 74, 79, 85, 92, 97, 102, 109, 119, 121, 124, 126, 131, 136, 142, 144, 148, 153, 159, 166, 170, 175, 181, 188, 193, 198, 204, 213, 221, 228, 238, 240, 244, 249, 255, 262, 266, 271, 277
Offset: 0

Views

Author

Antti Karttunen, Nov 25 2012

Keywords

Comments

a(n) tells in what number we end in n steps, when we start climbing up the infinite trunk of the "factorial beanstalk" from its root (zero).
There are many finite sequences such as 0,1,2,4; 0,1,2,5,6; etc. obeying the same condition (see A219659) and as the length increases, so (necessarily) does the similarity to this infinite sequence.
See A007623 for the factorial number system representation.

Crossrefs

Cf. A007623, A034968, A219651, A230411, A226061. For all n, A219652(a(n)) = n and A219653(n) <= a(n) <= A219655(n).
Characteristic function: Χ_A219666(n) = A230418(n+1)-A230418(n).
The first differences: A230406.
Subsets: A230428 & A230429.
Analogous sequence for binary system: A179016, for Fibonacci number system: A219648.

Programs

  • Mathematica
    nn = 10^3; m = 1; While[m! < Floor[6 nn/5], m++]; m; t = TakeWhile[Reverse@ NestWhileList[# - Total@ IntegerDigits[#, MixedRadix[Reverse@ Range[2, m]]] &, Floor[6 nn/5], # > 0 &], # <= nn &] (* Michael De Vlieger, Jun 27 2016, Version 10.2 *)
  • Scheme
    ;; Memoizing definec-macro from Antti Karttunen's IntSeq-library
    (definec (A219666 n) (cond ((<= n 2) n) ((= (A226061 (A230411 n)) n) (- (A000142 (A230411 n)) 1)) (else (- (A219666 (+ n 1)) (A034968 (A219666 (+ n 1)))))))
    ;; Another variant, utilizing A230416 (which gives a more convenient way to compute large number of terms of this sequence):
    (define (A219666 n) (A230416 (A230432 n)))
    ;; This function is for checking whether n belongs to this sequence:
    (define (inA219666? n) (or (zero? n) (= 1 (- (A230418 (+ 1 n)) (A230418 n)))))

Formula

a(0) = 0, a(1) = 1, and for n>1, if A226061(A230411(n)) = n then a(n) = A230411(n)!-1, otherwise a(n) = a(n+1) - A034968(a(n+1)).
a(n) = A230416(A230432(n)).

A219651 a(n) = n minus (sum of digits in factorial base expansion of n).

Original entry on oeis.org

0, 0, 1, 1, 2, 2, 5, 5, 6, 6, 7, 7, 10, 10, 11, 11, 12, 12, 15, 15, 16, 16, 17, 17, 23, 23, 24, 24, 25, 25, 28, 28, 29, 29, 30, 30, 33, 33, 34, 34, 35, 35, 38, 38, 39, 39, 40, 40, 46, 46, 47, 47, 48, 48, 51, 51, 52, 52, 53, 53, 56, 56, 57, 57, 58, 58, 61, 61
Offset: 0

Views

Author

Antti Karttunen, Nov 25 2012

Keywords

Comments

See A007623 for the factorial base number system representation.

Crossrefs

Bisection: A219650. Analogous sequence for binary system: A011371, for Zeckendorf expansion: A219641.

Programs

  • Mathematica
    (* First run program for A007623 to define factBaseIntDs *) Table[n - Plus@@factBaseIntDs[n], {n, 0, 99}] (* Alonso del Arte, Nov 25 2012 *)
  • Python
    from itertools import count
    def A219651(n):
        c, f = 0, 1
        for i in count(2):
            f *= i
            if f>n:
                break
            c += (i-1)*(n//f)
        return c # Chai Wah Wu, Oct 11 2024
  • Scheme
    (define (A219651 n) (- n (A034968 n)))
    

Formula

a(n) = n - A034968(n).

A219652 Number of steps to reach 0 starting with n and using the iterated process: x -> x - (sum of digits in factorial expansion of x).

Original entry on oeis.org

0, 1, 2, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19
Offset: 0

Views

Author

Antti Karttunen, Nov 25 2012

Keywords

Comments

See A007623 for the factorial number system representation.

Crossrefs

Analogous sequence for binary system: A071542, for Zeckendorf expansion: A219642. Cf. A007623, A034968, A219650, A219651, A219653-A219655, A219659, A219661, A219666.

Programs

  • Mathematica
    nn = 72; m = 1; While[Factorial@ m < nn, m++]; m; Table[Length@ NestWhileList[# - Total@ IntegerDigits[#, MixedRadix[Reverse@ Range[2, m]]] &, n, # > 0 &] - 1, {n, 0, nn}] (* Michael De Vlieger, Jun 27 2016, Version 10.2 *)

Formula

a(0)=0; for n>0, a(n) = 1 + a(A219651(n)).

Extensions

Erroneous description corrected by Antti Karttunen, Dec 03 2012

A219653 Least inverse of A219652; a(n) = minimal i such that A219652(i) = n.

Original entry on oeis.org

0, 1, 2, 4, 6, 8, 12, 16, 20, 24, 26, 30, 34, 38, 42, 48, 52, 56, 60, 66, 72, 78, 84, 90, 96, 102, 108, 116, 120, 122, 126, 130, 134, 138, 144, 148, 152, 156, 162, 168, 174, 180, 186, 192, 198, 204, 212, 218, 226, 234, 240, 244, 248, 252, 258, 264, 270, 276
Offset: 0

Views

Author

Antti Karttunen, Nov 25 2012

Keywords

Crossrefs

Cf. A219655 for the greatest inverse. A219654 gives the first differences.
This sequence is based on Factorial number system: A007623. Analogous sequence for binary system: A213708 and for Zeckendorf expansion: A219643. Cf. A219652, A219659, A219666.

A219645 Greatest inverse of A219642; a(n) = maximal i such that A219642(i) = n.

Original entry on oeis.org

0, 1, 2, 4, 6, 7, 9, 12, 14, 17, 20, 22, 25, 28, 31, 33, 35, 38, 41, 44, 46, 49, 53, 54, 56, 59, 62, 65, 67, 70, 74, 77, 80, 83, 88, 90, 93, 96, 99, 101, 104, 108, 111, 114, 117, 122, 125, 129, 133, 137, 142, 143, 145, 148, 151, 154, 156, 159, 163, 166, 169
Offset: 0

Views

Author

Antti Karttunen, Nov 24 2012

Keywords

Crossrefs

Cf. A219643 for the least inverse. A219644 gives the first differences.
This sequence is based on Fibonacci number system (Zeckendorf expansion): A014417. Analogous sequence for binary system: A173601, for factorial number system: A219655.

Formula

a(n) = A219643(n)+A219644(n)-1.

A219654 Run lengths in A219652.

Original entry on oeis.org

1, 1, 2, 2, 2, 4, 4, 4, 4, 2, 4, 4, 4, 4, 6, 4, 4, 4, 6, 6, 6, 6, 6, 6, 6, 6, 8, 4, 2, 4, 4, 4, 4, 6, 4, 4, 4, 6, 6, 6, 6, 6, 6, 6, 6, 8, 6, 8, 8, 6, 4, 4, 4, 6, 6, 6, 6, 6, 6, 6, 6, 8, 6, 8, 8, 6, 8, 10, 6, 6, 6, 6, 6, 6, 6, 8, 6, 8, 8, 6, 8, 10, 8, 10, 12, 6
Offset: 0

Views

Author

Antti Karttunen, Nov 25 2012

Keywords

Comments

a(n) tells from how many starting values one can end to 0 in n steps, with the iterative process described in A219652 (if going around in 0->0 loop is disallowed).

Crossrefs

a(n) = 1+(A219655(n)-A219653(n)). This sequence is based on Factorial number system: A007623. Analogous sequence for binary system: A086876, for Zeckendorf expansion: A219644. Cf. A219652, A219659, A219666.

Formula

a(n) = A219653(n+1)-A219653(n). (The first differences of A219653).

A255055 Greatest inverse of A255072; a(n) = largest k such that A255072(k) = n.

Original entry on oeis.org

0, 2, 5, 6, 10, 13, 14, 18, 22, 26, 29, 30, 34, 38, 43, 46, 50, 54, 58, 61, 62, 66, 70, 75, 78, 85, 90, 94, 98, 102, 107, 110, 114, 118, 122, 125, 126, 130, 134, 139, 142, 149, 154, 158, 165, 171, 175, 181, 186, 190, 194, 198, 203, 206, 213, 218, 222, 226, 230, 235, 238, 242, 246, 250, 253, 254, 258
Offset: 0

Views

Author

Antti Karttunen, Feb 14 2015

Keywords

Crossrefs

Analogous sequences: A173601, A219645, A219655.

Formula

a(0) = 0; for n > 0, a(n) = A255054(n) + a(n-1).
Other identities. For all n >= 0:
a(n) = A255053(n) + A255054(n) - 1.
a(n) = A255056(n) + A255124(n).

A231723 a(n) = the difference between the n-th node of the infinite trunk of the factorial beanstalk (A219666(n)) and the smallest integer (A219653(n)) which is as many A219651-iteration steps distanced from the root (zero); a(n) = A219666(n) - A219653(n).

Original entry on oeis.org

0, 0, 0, 1, 1, 2, 0, 1, 3, 1, 2, 0, 1, 2, 4, 0, 0, 1, 3, 4, 2, 1, 1, 2, 1, 0, 1, 3, 1, 2, 0, 1, 2, 4, 0, 0, 1, 3, 4, 2, 1, 1, 2, 1, 0, 0, 1, 3, 2, 4, 0, 0, 1, 3, 4, 2, 1, 1, 2, 1, 0, 0, 0, 0, 0, 0, 1, 3, 4, 2, 1, 1, 2, 1, 0, 0, 0, 0, 0, 0, 1, 3, 5, 7, 8, 1, 0
Offset: 0

Views

Author

Antti Karttunen, Nov 13 2013

Keywords

Comments

For all n, the following holds: A219653(n) <= A219666(n) <= A219655(n). This sequence gives the distance of the node n in the infinite trunk of factorial beanstalk (A219666(n)) from the left (lesser) edge of the A219654(n) wide window which it at that point must pass through.
This sequence relates to the factorial base representation (A007623) in the same way as A218603 relates to the binary system and similar remarks apply here.

Crossrefs

Programs

Formula

a(n) = A219666(n) - A219653(n).
A219654(n) = a(n) + A231724(n) + 1.
Showing 1-9 of 9 results.