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 1-10 of 30 results. Next

A094801 Numbers k such that k is a term of A014778, but k-1 and k+1 are not.

Original entry on oeis.org

13199998, 117463825, 513199998, 1111111110
Offset: 1

Views

Author

Lekraj Beedassy, Jun 11 2004

Keywords

References

  • M. Protat, Des Olympiades a l'Agregation, Nombre de "1", Problem 89, pp. 182-183, Ellipses, Paris 1997.

Crossrefs

Extensions

Corrected by David Wasserman, Jun 29 2007

A101640 Positive integers n for which n = f(n), where f(n) is the total number of 3's required when writing out all numbers between 0 and n.

Original entry on oeis.org

371599983, 371599984, 371599985, 371599986, 371599987, 371599988, 371599989, 371599990, 371599991, 371599992, 500000000, 10000000000, 10371599983, 10371599984, 10371599985, 10371599986, 10371599987, 10371599988
Offset: 1

Views

Author

Ryan Propper, Dec 10 2004

Keywords

Comments

Related to a problem posed by Google and discussed on the MathWorld link.
Together with the b-file, this gives the complete list of all 35 positive numbers n such that n is equal to the number of 3's in the decimal digits of all numbers <= n. - Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007

Examples

			a(1) = 371599983, since writing out all numbers from 0 to 371599983 requires that 371599983 3's be used and since 371599983 is the first such positive integer.
a(4) = 371599986 because the number of 3's in the decimal digits of the numbers from 1 to 371599986 is 371599986 and this is the 4th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101641, A130427, A130428, A130429, A130430, A130431; cf. A130432 for the number of numbers in these sequences.

Extensions

More terms from Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007

A101641 Positive integers n for which n = f(n), where f(n) is the total number of 4's required when writing out all numbers between 0 and n.

Original entry on oeis.org

499999984, 499999985, 499999986, 499999987, 499999988, 499999989, 499999990, 499999991, 499999992, 499999993, 500000000, 10000000000, 10499999984, 10499999985, 10499999986, 10499999987, 10499999988, 10499999989
Offset: 1

Views

Author

Ryan Propper, Dec 11 2004

Keywords

Comments

Related to a problem posed by Google and discussed on the MathWorld link.
Together with the b-file, this gives the complete list of all 47 positive numbers n such that n is equal to the number of 4's in the decimal digits of all numbers <= n. - Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007

Examples

			a(1) = 499999984, since writing out all numbers from 0 to 499999984 requires that 499999984 4's be used and since 499999984 is the first such positive integer.
a(4) = 499999987 because the number of 4's in the decimal digits of the numbers from 1 to 499999987 is 499999987 and this is the 4th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A130427, A130428, A130429, A130430, A130431; cf. A130432 for the number of numbers in these sequences.

Formula

a(n) = 499999983 + n, n <= 10; a(n) = 500000000, n = 11

Extensions

More terms from Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007
Keyword added by Charles R Greathouse IV, Jul 22 2010

A130428 List of numbers n such that n is equal to the number of 6's in the decimal digits of all numbers <= n.

Original entry on oeis.org

0, 9500000000, 9628399986, 9628399987, 9628399988, 9628399989, 9628399990, 9628399991, 9628399992, 9628399993, 9628399994, 9628399995, 10000000000, 19500000000, 19628399986, 19628399987, 19628399988, 19628399989
Offset: 1

Views

Author

Graeme McRae, May 26 2007

Keywords

Comments

A finite sequence with 72 terms.

Examples

			a(5)=9628399988 because the number of 6's in the decimal digits of the numbers from 0 to 9628399988 is 9628399988 and this is the 5th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A101641, A130427, A130429, A130430, A130431; Cf. A130432 for the number of numbers in these sequences.

A130429 List of all numbers n such that n is equal to the number of 7's in the decimal digits of all numbers <= n.

Original entry on oeis.org

0, 9465000000, 9471736170, 9500000000, 9757536170, 9965000000, 9971736170, 10000000000, 19465000000, 19471736170, 19500000000, 19757536170, 19965000000, 19971736170, 20000000000, 29465000000, 29471736170
Offset: 1

Views

Author

Graeme McRae, May 26 2007

Keywords

Comments

A finite sequence with 49 terms.

Examples

			a(5)=9757536170 because the number of 7's in the decimal digits of the numbers from 0 to 9757536170 is 9757536170 and this is the 5th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A101641, A130427, A130428, A130430, A130431; Cf. A130432 for the number of numbers in these sequences.

A130430 List of numbers n such that n is equal to the number of 8's in the decimal digits of all numbers <= n.

Original entry on oeis.org

0, 9465000000, 9486799989, 9486799990, 9486799991, 9486799992, 9486799993, 9486799994, 9486799995, 9486799996, 9486799997, 9497400000, 9498399989, 9498399990, 9498399991, 9498399992, 9498399993, 9498399994, 9498399995
Offset: 1

Views

Author

Graeme McRae, May 26 2007

Keywords

Comments

A finite sequence with 344 terms.

Examples

			a(5)=9486799991 because the number of 8's in the decimal digits of the numbers from 0 to 9486799991 is 9486799991 and this is the 5th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A101641, A130427, A130428, A130429, A130431; Cf. A130432 for the number of numbers in these sequences.

A101639 Positive integers n for which n = f(n), where f(n) is the total number of 2's required when writing out all numbers between 0 and n.

Original entry on oeis.org

28263827, 35000000, 242463827, 500000000, 528263827, 535000000, 10000000000, 10028263827, 10035000000, 10242463827, 10500000000, 10528263827, 10535000000
Offset: 1

Views

Author

Ryan Propper, Dec 10 2004

Keywords

Comments

Related to a problem posed by Google and discussed on the MathWorld link.
This is the complete list of all 13 positive numbers n such that n is equal to the number of 2's in the decimal digits of all numbers <= n. - Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007

Examples

			a(1) = 28263827 since writing out all numbers from 0 to 28263827 requires that 28263827 2's be used and since 28263827 is the first such positive integer.
a(4) = 500000000 because the number of 2's in the decimal digits of the numbers from 1 to 500000000 is 500000000 and this is the 4th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101640, A101641, A130427, A130428, A130429, A130430, A130431; cf. A130432 for the number of numbers in these sequences.

Extensions

More terms from Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007

A130427 Complete list of all 5 numbers n such that n is equal to the number of 5's in the decimal digits of all numbers <= n.

Original entry on oeis.org

0, 10000000000, 20000000000, 30000000000, 40000000000
Offset: 1

Views

Author

Graeme McRae, May 26 2007

Keywords

Examples

			a(5) = 40000000000 because the number of 5's in the decimal digits of the numbers from 0 to 40000000000 is 40000000000 and this is the 5th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A101641, A130428, A130429, A130430, A130431; Cf. A130432 for the number of numbers in these sequences.

A130431 Complete list of all 9 numbers n such that n is equal to the number of 9's in the decimal digits of all numbers <= n.

Original entry on oeis.org

0, 10000000000, 20000000000, 30000000000, 40000000000, 50000000000, 60000000000, 70000000000, 80000000000
Offset: 1

Views

Author

Graeme McRae, May 26 2007

Keywords

Examples

			a(5)=40000000000 because the number of 9's in the decimal digits of the numbers from 0 to 40000000000 is 40000000000 and this is the 5th such number.
		

Crossrefs

Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A101641, A130427, A130428, A130429, A130430; Cf. A130432 for the number of numbers in these sequences.

A130432 For digit n from 1 to 9, a(n) = the number of numbers m such that m is equal to the number of n's in the decimal digits of all numbers <= m.

Original entry on oeis.org

84, 14, 36, 48, 5, 72, 49, 344, 9
Offset: 1

Views

Author

Graeme McRae, May 26 2007

Keywords

Comments

Note: sequences A101639, A101640 and A101641 are defined so that they exclude 0, so they have 13, 35 and 47 elements, respectively. This sequence counts all the zeros, so elements 2,3,4 of this sequence are 14,36,48.

Examples

			a(3)=36 because there are 36 numbers m such that m is equal to the number of 3's in the decimal digits of all numbers <= m.
		

Crossrefs

See A014778 for proof that these sequences are finite and also A101639, A101640, A101641, A130427, A130428, A130429, A130430, A130431 for the numbers themselves.
Showing 1-10 of 30 results. Next