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 1-3 of 3 results.

A109986 Primes ordered alphabetically by where they occur in A000052.

Original entry on oeis.org

5, 7, 3, 2, 89, 83, 11, 59, 53, 41, 47, 43, 19, 97, 17, 79, 71, 73, 61, 67, 13, 31, 37, 29, 23, 881, 887, 883, 811, 859, 857, 853, 809, 877, 863, 839, 829, 821, 827, 823, 587, 557, 541, 547, 509, 599, 593, 571, 577, 569, 563, 503, 521, 523, 487, 457, 449, 443
Offset: 1

Views

Author

Jonathan Vos Post, Jul 07 2005

Keywords

Comments

A109987 is semiprimes ordered alphabetically by where they occur in A000052. A109988 is 3-almost primes ordered alphabetically by where they occur in A000052.

Examples

			a(1) = 5 because five is the first prime in alphabetical order.
a(5) = 89 because eighty-nine is the first 2-digit prime in alphabetical order.
		

Crossrefs

Programs

  • Maple
    V:= [seq(select(isprime, [$10^i..10^(i+1)-1]),i=0..3)]:
    seq(op(V[i][sort(map(convert,V[i],english,'And'),
    output=permutation)]),i=1..nops(V)); # Robert Israel, Jun 17 2016
  • Mathematica
    alph = Last /@ Import["https://oeis.org/A000052/b000052.txt", "Table"]; Take[
    Select[alph, PrimeQ], 58] (* Giovanni Resta, Jun 17 2016 *)

Extensions

Corrected and extended by Giovanni Resta, Jun 17 2016

A109988 3-almost primes (A014612) ordered alphabetically by where they occur in A000052.

Original entry on oeis.org

8, 18, 50, 52, 45, 44, 42, 98, 99, 92, 70, 78, 75, 76
Offset: 1

Views

Author

Jonathan Vos Post, Jul 07 2005

Keywords

Comments

A109986 is primes ordered alphabetically by where they occur in A000052. A109987 is semiprimes ordered alphabetically by where they occur in A000052. A109989 is 4-almost primes ordered alphabetically by where they occur in A000052.

Examples

			a(1) = 8 because eight is the first 3-almost prime in alphabetical order.
a(4) = 18 because eighteen is the first 2-digit 3-almost prime in alphabetical order.
		

Crossrefs

A109989 4-almost primes (A014613) ordered alphabetically by where they occur in A000052.

Original entry on oeis.org

88, 84, 81, 54, 56, 40, 90
Offset: 1

Views

Author

Jonathan Vos Post, Jul 07 2005

Keywords

Comments

A109986 is primes ordered alphabetically by where they occur in A000052. A109987 is semiprimes ordered alphabetically by where they occur in A000052. A109988 is 3-almost primes ordered alphabetically by where they occur in A000052.

Examples

			a(1) = 88 because eighty-eight is the first 4-almost prime in alphabetical order, there being no 1-digit 4-almost primes.
a(2) = 84 because eighty-four is the second 2-digit 4-almost prime in alphabetical order.
		

Crossrefs

Showing 1-3 of 3 results.