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.

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A352538 Primes whose position in the Wythoff array is immediately followed by another prime in the next column.

Original entry on oeis.org

2, 3, 7, 19, 23, 29, 67, 97, 103, 107, 149, 181, 227, 271, 311, 353, 379, 433, 449, 563, 631, 719, 761, 883, 919, 941, 971, 997, 1049, 1087, 1223, 1291, 1297, 1427, 1447, 1453, 1531, 1601, 1627, 1699, 1753, 1831, 1861, 1877, 2039, 2207, 2213, 2239, 2269, 2281, 2287
Offset: 1

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Author

Michel Marcus, Mar 20 2022

Keywords

Examples

			The Wythoff array begins:
   1    2    3    5    8 ...
   4    7   11   18   29 ...
   6   10   16   26   42 ...
   ...
So 2, 3 and 7 are terms, since they are horizontally followed by 3, 5 and 11.
		

Crossrefs

Cf. A003603, A022342, A035612, A035513 (Wythoff array).
Cf. A352537 (next row and column), A352539 (next row).

Programs

  • PARI
    T(n,k) = (n+sqrtint(5*n^2))\2*fibonacci(k+1) + (n-1)*fibonacci(k); \\ A035513
    cell(n) = for (r=1, oo, for (c=1, oo, if (T(r,c) == n, return([r, c])); if (T(r,c) > n, break);););
    isokh(m) = {my(pos = cell(prime(m))); isprime (T(pos[1], pos[2]+1))};
    lista(nn) = for (n=1, nn, if (isokh(n), print1(prime(n), ", ")));
    
  • PARI
    right(n) = n++; (sqrtint(5*n^2)+n-2)\2; \\ see A022342
    isokh(n) = isprime(right(n));
    lista(nn) = for (n=1, nn, my(p=prime(n)); if (isokh(p), print1(p, ", ")));

A352537 Primes whose position in the Wythoff array is immediately followed by a prime both in the next column and the next row.

Original entry on oeis.org

2, 3, 919, 1223, 1699, 3329, 8009, 11717, 13691, 19079, 20921, 21011, 22643, 22739, 24623, 26309, 28571, 28619, 28979, 30389, 33629, 34739, 35257, 41179, 42577, 48647, 54133, 58601, 59627, 61511, 65171, 70979, 75707, 80141, 84221, 86869, 90677, 93557, 94781
Offset: 1

Views

Author

Michel Marcus, Mar 20 2022

Keywords

Examples

			The Wythoff array begins:
   1    2    3    5   ...
   4    7   11   18   ...
   6   10   16   26   ...
   ...
where one can see these 2 patterns:
   2    3   and   3    5
   7             11
so 2 and 3 are terms.
		

Crossrefs

Cf. A003603, A035612, A035513 (Wythoff array).
Intersection of A352538 and A352539.

Programs

  • PARI
    T(n,k) = (n+sqrtint(5*n^2))\2*fibonacci(k+1) + (n-1)*fibonacci(k); \\ A035513
    cell(n) = for (r=1, oo, for (c=1, oo, if (T(r,c) == n, return([r, c])); if (T(r,c) > n, break);););
    isokp(m) = my(pos = cell(prime(m))); isprime (T(pos[1], pos[2]+1)) && isprime(T(pos[1]+1, pos[2]));
    lista(nn) = for (n=1, nn, if (isokp(n), print1(prime(n), ", ")));
Showing 1-2 of 2 results.