Yes, there is such a thing as a good prime and it is defined as follows:
A prime \(p_n\) is said to be \( \textbf{good} \) if \(p_n^{^\textbf{2}}>p_{n-i } \cdot p_{n+i} \) for all \( 1 \leq i < n \).
The term was drawn to my attention because the prime associated with my diurnal age today (27737) and its earlier cousin prime (27733) are both good primes. The initial good primes are:
5, 11, 17, 29, 37, 41, 53, 59, 67, 71, 97, 101, 127, 149, 179, 191, 223, 227, 251, 257, 269, 307, 311, 331, 347, 419, 431, 541, 557, 563, 569, 587, 593, 599, 641, 727, 733, 739, 809, 821, 853
Let's look at 17 as an example where \(17^2=289\). The primes less than it are 2, 3, 5, 7, 11 and 13. The corresponding primes larger than it are 43, 37, 31, 29, 23 and 19. So we have:$$ \begin{align} 2 \times 43 &= 86 < 289 \\ 3 \times 37 &= 111 < 289 \\ 5 \times 31 &=155 < 289 \\ 7 \times 29 &=203 < 289 \\ 11 \times 23 &= 253 < 289 \\ 13 \times 19 &= 247 < 289 \end{align}$$The earliest runs of 2, 3, 4, 5, 6 and 7 consecutive good primes start at 37, 557, 1847, 216703, 6929381, 134193727 and 15118087477. The good primes from 27733 to 40000 are as follows (permalink):
27733, 27737, 28277, 28387, 28403, 28493, 28537, 28571, 28591, 28597, 29833, 29983, 30011, 30059, 30089, 30491, 30631, 30637, 30671, 30757, 30803, 31121, 31139, 31147, 31957, 32027, 32051, 32057, 32297, 32969, 33287, 33311, 33329, 34123, 35729, 35747, 35797, 35801, 35831, 35951, 35963, 36433, 36451, 36467, 36523, 36527, 36671, 38113, 38149, 38167, 38177, 38543, 38557, 38593, 38651, 38669, 39079, 39089
Clearly the primes above and below the aspiring good prime need to be fairly bunched up, especially the ones above, and this is indeed the case for 27733 and 27737.
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