cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A339935 Primes p such that p+(p^2-1)/6 is a square.

Original entry on oeis.org

5, 29, 73, 313, 71477281, 297316321, 271351716183549149, 645761700848255113, 233017713343294737292495403306881, 521760494347510297716737304478850311229
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Dec 23 2020

Keywords

Comments

p + (p^2-1)/6 is the square of a prime for primes p = 5, 29 and 73. Are there any others?

Examples

			a(3)=73 is a term because 73 is prime and 73+(73^2-1)/6 = 961 = 31^2 is a square.
		

Crossrefs

Programs

  • Maple
    f:= gfun:-rectoproc({a(i+4)-10*a(i+2)+a(i)=24,a(0)=1,a(1)=1,a(2)=5,a(3)=29},a(i),remember):
    select(isprime, map(f, [$1..100]));
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