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.

A384676 Binomial transform of A111107.

Original entry on oeis.org

2, 5, 13, 37, 101, 271, 727, 1931, 5003, 12547, 30449, 71761, 165037, 372149, 826303, 1813219, 3944921, 8533073, 18393821, 39588071, 85192381, 183479291, 395667617, 854417989, 1847225579, 3996807053, 8650687127, 18721431499, 40496966207, 87538925959, 189076973699
Offset: 0

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Author

Alois P. Heinz, Jun 06 2025

Keywords

Comments

All terms are primes.

Crossrefs

Formula

a(n) = Sum_{i=0..n} A111107(n-i) * binomial(n,i).

A384674 Lexicographically smallest sequence of distinct primes whose inverse binomial transform consists only of primes.

Original entry on oeis.org

2, 5, 11, 23, 47, 97, 211, 491, 1187, 2857, 6659, 14879, 31891, 65929, 132469, 261059, 510031, 999721, 1988797, 4048339, 8450557, 18014701, 38902439, 84347189, 182269327, 390630769, 828123239, 1735146097, 3594509969, 7369765889, 14975024861, 30200498591, 60537295711
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; local b, p;
          b:= add(a(n-i)*binomial(n, i)*(-1)^i, i=1..n);
          p:= nextprime(abs(b));
          do if isprime(p+b) then break fi ;
             p:= nextprime(p)
          od; p
        end: a(0):=2:
    seq(a(n), n=0..32);  # Alois P. Heinz, Jun 06 2025
  • Mathematica
    a[n_] := a[n] = Module[{b, p}, b = Sum[a[n-i]*Binomial[n, i]*(-1)^i, {i, 1, n}]; p = NextPrime[Abs[b]]; While[True, If[PrimeQ[p+b], Break[]]; p = NextPrime[p]]; p];
    a[0] = 2;
    Table[a[n], {n, 0, 32}] (* Jean-François Alcover, Aug 28 2025, after Alois P. Heinz *)

Extensions

More terms from Alois P. Heinz, Jun 06 2025

A384768 Inverse binomial transform of A384674.

Original entry on oeis.org

2, 3, 3, 3, 3, 5, 11, 13, 7, 5, 7, 5, 3, 17, 29, 11, 11, 17, 13, 7, 29, 3, 3, 23, 3, 17, 37, 5, 223, 5, 37, 59, 19, 23, 433, 13, 89, 7, 7, 43, 3, 61, 5, 3, 191, 61, 149, 43, 89, 71, 13, 43, 41, 79, 31, 61, 23, 73, 53, 11, 157, 197, 83, 163, 3, 47, 7, 109, 5
Offset: 0

Views

Author

Keywords

Comments

All terms are primes.

Crossrefs

Formula

a(n) = Sum_{i=0..n} (-1)^(n-i) * A384674(i) * binomial(n,i).
Showing 1-3 of 3 results.