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A167843
Obtuse-angled primes.
5
113, 127, 137, 139, 149, 157, 167, 179, 199, 211, 223, 227, 229, 233, 239, 257, 269, 277, 311, 331, 337, 347, 349, 359, 367, 379, 389, 421, 431, 433, 443, 449, 457, 467, 479, 499, 521, 541, 557, 569, 577, 599, 631, 641, 643, 653, 661, 677, 733, 743, 751, 761
OFFSET
1,1
COMMENTS
Primes in A135603.
Primes whose structure of digits represents an obtuse angle. The vertex is an internal digit. In the graphic representation the points are connected by imaginary line segments from left to right.
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..914
PROG
(Python) # uses agen() from A135603
from sympy import isprime
g = filter(isprime, agen())
print([next(g) for n in range(1, 53)]) # Michael S. Branicky, Aug 03 2022
KEYWORD
base,nonn
AUTHOR
Omar E. Pol, Nov 13 2009
EXTENSIONS
a(12) and beyond from Michael S. Branicky, Aug 03 2022
STATUS
approved