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 1-4 of 4 results.

A278743 For a base n>1: consider the lexicographically least strictly increasing sequence c_n such that, for any m>0, Sum_{k=1..m} c_n(k) can be computed without carries in base n; the sequence c_n is (conjecturally) eventually linear, and a(n) gives its order.

Original entry on oeis.org

1, 3, 2, 5, 9, 3, 7, 4, 17, 4, 9, 15, 21, 11, 5, 11, 25, 25, 13, 7, 6, 13, 7, 29, 15, 16, 25, 7, 15, 9, 33, 17, 10, 28, 57, 8, 17, 49, 37, 19, 10, 31, 63, 21, 9, 19, 43, 41, 21, 34, 34, 69, 23, 12, 10, 21, 13, 45, 23, 51, 37, 75, 25, 13, 67, 11, 23, 42, 49, 25
Offset: 2

Views

Author

Rémy Sigrist, Nov 27 2016

Keywords

Comments

More precisely, we conjecture that, for any n>1, there are two constants k0 and b such that c_n(k + a(n)) = c_n(k)*n^b for any k>k0. [Corrected by Rémy Sigrist, Dec 24 2016]
For the values of k0 and b see A280051 and A280052. - N. J. A. Sloane, Jan 06 2017

Examples

			c_2 = A000079, and A000079 has order 1, hence a(2)=1.
c_10 = A278742, and A278742 has order 17, hence a(10)=17.
See also Links section.
		

Crossrefs

Formula

a(A000124(n)) = n for any n>0.
a(A000124(n)+1) = 2*n + 1 for any n>0.

A280051 Let c_n(k) be the sequence defined in A278743; here we give the associated values of k0.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 0, 0, 22, 0, 0, 15, 11, 0, 0, 11, 0, 0, 7, 12, 0, 0, 0, 0, 0, 0, 24, 13, 0, 0, 0, 0, 0, 0, 0, 0, 14, 0, 0, 27, 0, 0, 29, 0, 0, 0, 15, 0, 0, 29, 29, 0, 0, 15, 0, 0, 18, 16, 0, 0, 31, 31, 34, 0, 0, 16
Offset: 2

Views

Author

N. J. A. Sloane, Jan 06 2017

Keywords

Comments

Let c_n(k) be the sequence defined in A278743, for n >= 2. It is conjectured that there are numbers k0 and b such that c_n(k) satisfies the recurrence c_n(k + A278743(n)) = c_n(k)*n^b for k > k0. Here we give the values of k0. The values of b are given in A280052.

Crossrefs

Extensions

More terms from Rémy Sigrist, Jan 07 2017

A280731 Lexicographically least strictly increasing sequence such that, for any n>0, Sum_{k=1..n} a(k) can be computed without carries in base 9 (the numbers are written in base 10).

Original entry on oeis.org

1, 2, 3, 9, 10, 18, 19, 81, 90, 162, 171, 729, 810, 1458, 1539, 6561, 7290, 13122, 13851, 59049, 65610, 118098, 124659, 531441, 590490, 1062882, 1121931, 4782969, 5314410, 9565938, 10097379, 43046721, 47829690, 86093442, 90876411, 387420489, 430467210
Offset: 1

Views

Author

N. J. A. Sloane, Jan 09 2017

Keywords

Comments

Base 9 analog of A278742.

Crossrefs

See A281366 for these numbers written in base 9.

Programs

  • Mathematica
    LinearRecurrence[{0,0,0,9},{1,2,3,9,10,18,19},50] (* Harvey P. Dale, Feb 28 2022 *)
  • PARI
    Vec(x*(1 + 2*x + 3*x^2 + 9*x^3 + x^4 - 8*x^6) / ((1 - 3*x^2)*(1 + 3*x^2)) + O(x^50)) \\ Colin Barker, Jan 10 2017

Formula

For k>7, a(k+4) = 9*a(k).
G.f.: x*(1 + 2*x + 3*x^2 + 9*x^3 + x^4 - 8*x^6) / ((1 - 3*x^2)*(1 + 3*x^2)). - Colin Barker, Jan 10 2017

A281366 Lexicographically least strictly increasing sequence such that, for any n>0, Sum_{k=1..n} a(k) can be computed without carries in base 9 (the numbers are written in base 9).

Original entry on oeis.org

1, 2, 3, 10, 11, 20, 21, 100, 110, 200, 210, 1000, 1100, 2000, 2100, 10000, 11000, 20000, 21000, 100000, 110000, 200000, 210000, 1000000, 1100000, 2000000, 2100000, 10000000, 11000000, 20000000, 21000000, 100000000, 110000000, 200000000, 210000000
Offset: 1

Views

Author

N. J. A. Sloane, Jan 28 2017

Keywords

Comments

Base 9 analog of A278742.

Crossrefs

See A280731 for these numbers written in base 10.

Programs

  • PARI
    Vec(x*(1 + 2*x + 3*x^2 + 10*x^3 + x^4 - 9*x^6) / (1 - 10*x^4) + O(x^60)) \\ Colin Barker, Jan 29 2017

Formula

From Colin Barker, Jan 29 2017: (Start)
G.f.: x*(1 + 2*x + 3*x^2 + 10*x^3 + x^4 - 9*x^6)/(1 - 10*x^4).
a(n) = 10*a(n-4) for n>7. (End)

Extensions

More terms from Colin Barker, Jan 29 2017
Showing 1-4 of 4 results.