A139221 -id:A139221 - cp's OEIS frontend

A139219 Primes of the form 41+(n+n^2)/2=41+A000217(n).

41, 47, 107, 251, 317, 419, 569, 821, 1031, 1217, 1367, 1637, 1811, 1871, 3527, 5501, 5927, 6257, 6827, 8297, 8819, 9221, 10337, 14747, 17807, 20747, 21569, 22619, 25919, 28961, 31667, 34757, 37991, 43997, 45191, 48869, 49811, 52691, 63587

Offset: 1

Zak Seidov, Apr 11 2008

Corresponding values of n in A139220.

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A000217, A056561, A139220, A139221.

[a: n in [0..500] | IsPrime(a) where a is  41 +(n + n^2) div 2]; // Vincenzo Librandi, Mar 22 2013

Select[Table[41+(n+n^2)/2,{n,0,800}],PrimeQ]

A139220 Numbers k such that 41+(k+k^2)/2 = 41+A000217(k) is prime.

Original entry on oeis.org

0, 3, 11, 20, 23, 27, 32, 39, 44, 48, 51, 56, 59, 60, 83, 104, 108, 111, 116, 128, 132, 135, 143, 171, 188, 203, 207, 212, 227, 240, 251, 263, 275, 296, 300, 312, 315, 324, 356, 359, 363, 380, 384, 392, 399, 408, 443, 447, 476, 479, 483, 504, 507, 515, 527, 528

Offset: 1

Zak Seidov, Apr 11 2008

nonn

Corresponding values of primes are in A139219.

Numbers k such that both 41+(k+k^2)/2 and 41+(k+k^2) are primes, are in A139221.

			If k = 11 then 41 + (k + k^2) / 2 = 107 (prime).

Cf. A000217, A056561, A139219, A139221.

[k:k in [0..530]| IsPrime(41+(k+k^2) div 2)]; // Marius A. Burtea, Feb 12 2020

Select[Table[Range[0,1000]],PrimeQ[41+(#+#^2)/2]&]

is(n)=isprime(n*(n+1)/2+41) \\ Charles R Greathouse IV, Aug 16 2015

cp's OEIS Frontend

A139219 Primes of the form 41+(n+n^2)/2=41+A000217(n).

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