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.

A355983 Primes whose reversal is a multiple of 4.

Original entry on oeis.org

23, 29, 61, 67, 211, 233, 239, 251, 257, 271, 277, 293, 401, 409, 421, 443, 449, 461, 463, 467, 487, 613, 617, 619, 631, 653, 659, 673, 677, 691, 809, 821, 823, 827, 829, 863, 881, 883, 887, 2111, 2113, 2129, 2131, 2137, 2141, 2143, 2153, 2161, 2179, 2309, 2311, 2333, 2339, 2341, 2347, 2351
Offset: 1

Views

Author

Bernard Schott, Jul 22 2022

Keywords

Comments

Equivalently, primes starting with 21, 23, 25, 27, 29, 40, 42, 44, 46, 48, 61, 63, 65, 67, 69, 80, 82, 84, 86, 88.
Subsequence of A355430.

Examples

			67 is a term since 67 is prime and 76 is divisible by 4.

Crossrefs

Primes whose reversal is a multiple of k: A355430 (k=2), {3} (k=3), this sequence (k=4), A045711 (k=5), A087762 (k=7), {11} (k=11), A087764 (k=13), A087765 (k=17), A087766 (k=19), A087767 (k=23).

Programs

  • Mathematica
    Select[Prime[Range[350]], Divisible[IntegerReverse[#], 4] &] (* Amiram Eldar, Jul 22 2022 *)
  • PARI
    isok(p) = isprime(p) && !(fromdigits(Vecrev(digits(p))) % 4); \\ Michel Marcus, Jul 22 2022

A355984 Primes whose reversal is a multiple of 8.

Original entry on oeis.org

23, 61, 211, 251, 257, 293, 401, 409, 443, 449, 487, 631, 673, 677, 821, 823, 827, 829, 863, 2111, 2113, 2131, 2137, 2153, 2179, 2309, 2341, 2347, 2381, 2383, 2389, 2531, 2539, 2551, 2557, 2579, 2591, 2593, 2707, 2729, 2741, 2749, 2767, 2789, 2917, 2939, 2953, 2957
Offset: 1

Views

Author

Bernard Schott, Jul 25 2022

Keywords

Comments

Subsequence of A355430 and of A355983.

Examples

			251 is a term since 251 is prime and 152 = 8 * 19.

Crossrefs

Primes whose reversal is a multiple of k: A355430 (k=2), {3} (k=3), A355983 (k=4), A045711 (k=5), A087762 (k=7), this sequence (k=8), {11} (k=11), A087764 (k=13), A087765 (k=17), A087766 (k=19), A087767 (k=23)

Programs

  • Mathematica
    Select[Prime[Range[500]], Divisible[IntegerReverse[#], 8] &] (* Amiram Eldar, Jul 25 2022 *)
  • PARI
    is(n) = fromdigits(Vecrev(digits(n)))%8 == 0 \\ David A. Corneth, Jul 25 2022

Extensions

More terms from David A. Corneth, Jul 25 2022

A355985 Primes whose reversal is a multiple of 16.

Original entry on oeis.org

23, 61, 211, 257, 449, 487, 821, 829, 863, 2131, 2137, 2179, 2551, 2557, 2591, 2593, 2707, 2741, 2749, 2789, 2939, 2971, 4013, 4019, 4051, 4057, 4091, 4093, 4099, 4201, 4241, 4243, 4283, 4289, 4621, 4663, 4813, 4817, 6121, 6163, 6311, 6317, 6353, 6359, 6397
Offset: 1

Views

Author

Bernard Schott, Jul 29 2022

Keywords

Examples

			257 is a term since 257 is prime and 752 = 16 * 47.

Crossrefs

Subsequence of A355430, A355983 and A355984.
Primes whose reversal is a multiple of k: A355430 (k=2), {3} (k=3), A355983 (k=4), A045711 (k=5), A087762 (k=7), A355984 (k=8), {11} (k=11), A087764 (k=13), this sequence (k=16), A087765 (k=17), A087766 (k=19), A087767 (k=23).

Programs

  • Mathematica
    Select[Prime[Range[1000]], Divisible[IntegerReverse[#], 16] &] (* Amiram Eldar, Jul 29 2022 *)
  • PARI
    is(n) = { fromdigits(Vecrev(digits(n)))%16==0 && isprime(n) } \\ Rémy Sigrist, Jul 29 2022

Extensions

More terms from Rémy Sigrist, Jul 29 2022

A356246 Primes whose reversal is a multiple of 14.

Original entry on oeis.org

41, 89, 211, 223, 281, 293, 463, 487, 499, 691, 827, 839, 2129, 2213, 2237, 2333, 2357, 2441, 2477, 2503, 2539, 2647, 2659, 2693, 2731, 2767, 2851, 2887, 2971, 4021, 4057, 4091, 4153, 4177, 4261, 4273, 4297, 4409, 4517, 4637, 4649, 4721, 4733, 4877, 4889, 4903, 4973
Offset: 1

Views

Author

Bernard Schott, Jul 30 2022

Keywords

Comments

Intersection of A087762 and A355430.

Examples

			281 is a term since 281 is prime and 182 = 14 * 13.

Crossrefs

Primes whose reversal is a multiple of k: A074895 (k=1), A355430 (k=2), {3} (k=3), A355983 (k=4), A045711 (k=5), A087762 (k=7), A355984 (k=8), {11} (k=11), A087764 (k=13), this sequence (k=14), A355985 (k=16), A087765 (k=17), A087766 (k=19), A087767 (k=23).

Programs

  • Mathematica
    Select[Prime[Range[666]], Divisible[IntegerReverse[#], 14] &] (* Amiram Eldar, Jul 30 2022 *)
Showing 1-4 of 4 results.

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