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A226071
Numbers n such that triangular(n)+1 is a square and triangular(n)+2 is a prime.
3
0, 2, 5, 189, 3074, 218685
OFFSET
1,2
COMMENTS
Subsequence of A006451 that contains the terms n such that triangular(n)+2 is prime.
a(7) is too large to include here (see b-file). - Max Alekseyev, Jan 30 2014
LINKS
MATHEMATICA
Select[Range[0, 220000], IntegerQ[Sqrt[(#(#+1))/2+1]]&&PrimeQ[(#(#+1))/2+2]&] (* Harvey P. Dale, Mar 01 2023 *)
PROG
(C) // see A226069.
CROSSREFS
Corresponding primes: A226069.
Roots of corresponding squares: A226070.
Sequence in context: A124275 A013130 A111392 * A319143 A100366 A339313
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, May 25 2013
EXTENSIONS
Terms a(7)-a(12) from Max Alekseyev, Jan 30 2014
STATUS
approved