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.

User: J. Marcel Feenstra

J. Marcel Feenstra's wiki page.

J. Marcel Feenstra has authored 4 sequences.

A336094 Digit of Pi multiplied by the next digit of Pi.

Original entry on oeis.org

3, 4, 4, 5, 45, 18, 12, 30, 15, 15, 40, 72, 63, 63, 27, 6, 6, 24, 32, 24, 12, 12, 24, 12, 9, 24, 24, 6, 14, 63, 45, 0, 0, 16, 64, 32, 4, 9, 63, 7, 6, 54, 27, 27, 81, 27, 21, 35, 5, 0, 0, 40, 16, 0, 0, 63, 28, 36, 36, 16, 20, 45, 18, 6, 0, 0, 56, 8, 6, 24, 0, 0, 12, 16, 48
Offset: 1

Views

Author

J. Marcel Feenstra, Jul 08 2020

Keywords

Comments

There are 37 different values that can appear in this sequence, the last of which does not appear until a(560) = 49.

Examples

			The fifth digit of Pi is 5 and the sixth is 9, so a(5) = 45.

Crossrefs

Cf. A000796, A095916, A110883, A253828.

Programs

  • Mathematica
    d = RealDigits[Pi, 10, 76][[1]]; Most[d] * Rest[d] (* Amiram Eldar, Jul 08 2020 *)

A331482 Position of the first letter of n (in Dutch) in the alphabet.

Original entry on oeis.org

14, 5, 20, 4, 22, 22, 26, 26, 1, 14, 20, 5, 20, 4, 22, 22, 26, 26, 1, 14, 20, 5, 20, 4, 22, 22, 26, 26, 1, 14, 4, 5, 20, 4, 22, 22, 26, 26, 1, 14, 22, 5, 20, 4, 22, 22, 26, 26, 1, 14, 22, 5, 20, 4, 22, 22, 26, 26, 1, 14, 26, 5, 20, 4, 22, 22, 26, 26, 1, 14, 26
Offset: 0

Views

Author

J. Marcel Feenstra, Jan 18 2020

Keywords

Examples

			'Een' (Dutch for 'one') begins with 'E', the fifth letter of the alphabet, hence a(1)=5.

Links

Crossrefs

Cf. A005606 (English), A161377 (Spanish), A277685 (Portuguese).
Cf. other Dutch sequences: A090589, A247802.

Programs

  • Mathematica
    a[n_] := LetterNumber @ Characters[IntegerName[n, {"Dutch","Ordinal"}]][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jan 18 2020 *)
  • Python
    from num2words import num2words
import unidecode
def A331482(n):
    return ord(unidecode.unidecode(num2words(n, lang='nl')).lower()[0]) - 96 # Chai Wah Wu, Feb 27 2020

A331498 Position of the first letter of n (in French) in the alphabet.

Original entry on oeis.org

26, 21, 4, 20, 17, 3, 19, 19, 8, 14, 4, 15, 4, 20, 17, 17, 19, 4, 4, 4, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19
Offset: 0

Views

Author

J. Marcel Feenstra, Jan 18 2020

Keywords

Examples

			'Un' (French for 'one') begins with 'U', the twenty-first letter of the alphabet, hence a(1)=21.

Links

Crossrefs

Cf. A005606.

Programs

  • Mathematica
    a[n_] := LetterNumber @ Characters[IntegerName[n, "French"]][[1]]; Array[a, 100, 0]  (* Amiram Eldar, Jan 18 2020 *)
  • Python
    from num2words import num2words
import unidecode
def A331498(n):
    return ord(unidecode.unidecode(num2words(n, lang='fr')).lower()[0]) - 96 # Chai Wah Wu, Feb 27 2020

A331481 Position of the first letter of n-th (in English) in the alphabet.

Original entry on oeis.org

26, 6, 19, 20, 6, 6, 19, 19, 5, 14, 20, 5, 20, 20, 6, 6, 19, 19, 5, 14, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19
Offset: 0

Views

Author

J. Marcel Feenstra, Jan 18 2020

Keywords

Examples

			'First' begins with 'F', the sixth letter, hence a(1)=6.

Crossrefs

Cf. A005606 (analog for cardinal numbers).

Programs

  • Mathematica
    a[n_] := LetterNumber @ Characters[IntegerName[n, {"English","Ordinal"}]][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jan 18 2020 *)
  • Python
    from num2words import num2words
import unidecode
def A331481(n):
    return ord(unidecode.unidecode(num2words(n, to='ordinal')).lower()[0]) - 96 # Chai Wah Wu, Feb 27 2020

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