A322420 -id:A322420 - cp's OEIS frontend

A322421 Primes of the form A322420(k) or the sum of the first k*(k+1) primes.

5, 41, 197, 44683, 360979, 3619807, 5353841, 25106701, 47525059, 159781073, 188024357, 243458497, 445838927, 1015334371, 2018174117, 2079737563, 4925466041, 5294877781, 6383922529, 6531129499, 6680974507, 7635495793

Offset: 1

Ray Chandler, Dec 07 2018

nonn

Ray Chandler, Table of n, a(n) for n = 1..1000

Cf. A002378, A007504, A322420, A322422.

f[n_] := Sum[Prime[k], {k, n}]; Select[
Table[f[n*(n + 1)], {n, 0, 240}], PrimeQ]

a(n) = A007504(A002378(A322422(n))) = A322420(A322422(n)).

A109726 Divide primes in groups with 2n elements and add together.

Original entry on oeis.org

0, 5, 36, 156, 442, 954, 1854, 3154, 4998, 7514, 10784, 14786, 19932, 26148, 33448, 42340, 52208, 64322, 77898, 93116, 110224, 129978, 151990, 175224, 201584, 231272, 263500, 298590, 335856, 376616, 420984, 469894, 521740, 577304, 634990

Offset: 0

Giovanni Teofilatto, Aug 10 2005

First difference of A322420.

Ray Chandler, Table of n, a(n) for n = 0..10000

Cf. A007504, A109722-A109725, A322420.

f[n_] := Sum[Prime[k], {k, n}]; Table[f[n*(n + 1)] - f[n*(n - 1)], {n, 0, 34}]

a(n) = A007504(n*(n+1)) - A007504(n*(n-1)).

Edited and extended by Ray Chandler, Aug 11 2005

A322422 Numbers k such that the sum of the first k*(k+1) primes is prime.

Original entry on oeis.org

1, 2, 3, 11, 18, 31, 34, 49, 57, 76, 79, 84, 97, 118, 139, 140, 172, 175, 183, 184, 185, 191, 208, 218, 221, 232, 233, 247, 262, 266, 294, 313, 315, 323, 333, 334, 339, 344, 351, 361, 366, 372, 407, 413, 436, 445, 461, 473, 478, 500, 545, 546, 556, 564, 577

Offset: 1

Ray Chandler, Dec 07 2018

nonn

Ray Chandler, Table of n, a(n) for n = 1..1000

Cf. A002378, A007504, A322420, A322421.

f[n_] := Sum[Prime[k], {k, n}]; Select[Range[500],
PrimeQ[f[#*(# + 1)]] &]

A322421(n) = A322420(a(n)) = A007504(A002378(a(n))).

cp's OEIS Frontend

A322421 Primes of the form A322420(k) or the sum of the first k*(k+1) primes.

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A109726 Divide primes in groups with 2n elements and add together.

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Keywords

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Programs

Mathematica

Formula

Extensions

A322422 Numbers k such that the sum of the first k*(k+1) primes is prime.

Views

Author

Keywords

Links

Crossrefs

Programs

Mathematica

Formula