A285811 Primes equal to a centered heptagonal number plus 1.
2, 23, 107, 149, 317, 1619, 2459, 3257, 3929, 5189, 6029, 6323, 7247, 15017, 19427, 21023, 21569, 26189, 42737, 45887, 55127, 56009, 63317, 66173, 67139, 70079, 82469, 101747, 105359, 110273, 125687, 136523, 137909, 149249, 155087, 159539, 167099, 171719
Offset: 1
Keywords
Links
- Colin Barker, Table of n, a(n) for n = 1..1000
Programs
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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(7, k) + 1), listput(L, p))); Vec(L)
Comments