A285810 Primes equal to a centered pentagonal number plus 1.

2, 7, 17, 107, 227, 277, 457, 857, 1627, 3517, 4517, 5407, 9767, 11057, 13877, 15017, 16607, 20477, 23767, 26267, 27827, 35107, 37517, 41927, 42577, 50767, 53657, 58907, 62017, 68477, 79657, 83267, 86027, 93607, 98507, 110777, 113957, 128257, 137477, 145807

Offset

1,1

Links

Colin Barker, Table of n, a(n) for n = 1..1000

Prog

(PARI) cpg(m, n) = m*n*(n-1)/2+1 \\ n-th centered m-gonal number
maxk=600; L=List(); for(k=1, maxk, if(isprime(p=cpg(5, k) + 1), listput(L, p))); Vec(L)

Crossrefs

Cf. A000040, A005891, A285809, A285811, A285812.

Sequence in context: A283754 A122382 A025554 * A028888 A082627 A160617

Adjacent sequences: A285807 A285808 A285809 * A285811 A285812 A285813

Keyword

nonn

Author

Colin Barker, Apr 27 2017

Status

approved