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 A262182 Prime numbers of the form (n*(n+1)/2)^2 + 1. 1
 2, 37, 101, 1297, 4357, 14401, 44101, 90001, 164837, 246017, 608401, 894917, 1382977, 4326401, 8122501, 8561477, 9985601, 10497601, 38638657, 46049797, 52707601, 84272401, 121572677, 146168101, 165894401, 201526417, 259532101, 289680401, 404010001, 428738437 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sum_{n>=1} 1/a(n) = 0.538046187... LINKS Chai Wah Wu, Table of n, a(n) for n = 1..5231 FORMULA a(n) = A154323(A217755(n)). - Michel Marcus, Oct 02 2015 a(n) = ((A217755(n)^2 + A217755(n))/2)^2 + 1. - Jean C. Lambry, Oct 07 2015 PROG (Python 2.7) def prime (n):     if (n == 1): return True     d = n + 1     c = n - 1     while (c > 0 and d%c != 0):         d = d + n         c = c - 1     if (c == 1):         return True     else:         return False n = 1 i = 1 while (i <= 500):     target = i * (i + 1) / 2     if(prime(target) == True):         print n, target*target+1         n = n + 1     i = i + 1 \\ Jean C. Lambry, Oct 06 2015 (PARI) for(n=1, 1e3, if(isprime(k = (n*(n+1)/2)^2+1), print1(k", "))) \\ Altug Alkan, Oct 02 2015 CROSSREFS Cf. A154323, A217755. Sequence in context: A041161 A106947 A258896 * A142077 A107182 A134596 Adjacent sequences:  A262179 A262180 A262181 * A262183 A262184 A262185 KEYWORD nonn AUTHOR Jean C. Lambry, Oct 02 2015 EXTENSIONS More terms from Altug Alkan, Oct 02 2015 STATUS approved

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Last modified March 25 22:28 EDT 2019. Contains 321477 sequences. (Running on oeis4.)