A167843 - OEIS

%I #10 Aug 03 2022 18:36:33

%S 113,127,137,139,149,157,167,179,199,211,223,227,229,233,239,257,269,

%T 277,311,331,337,347,349,359,367,379,389,421,431,433,443,449,457,467,

%U 479,499,521,541,557,569,577,599,631,641,643,653,661,677,733,743,751,761

%N Obtuse-angled primes.

%C Primes in A135603.

%C 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.

%H Michael S. Branicky, <a href="/A167843/b167843.txt">Table of n, a(n) for n = 1..914</a>

%o (Python) # uses agen() from A135603

%o from sympy import isprime

%o g = filter(isprime, agen())

%o print([next(g) for n in range(1, 53)]) # _Michael S. Branicky_, Aug 03 2022

%Y Cf. A134811, A134951, A134971, A135603, A167841, A167842, A167844, A167845, A167846, A167853.

%K base,nonn

%O 1,1

%A _Omar E. Pol_, Nov 13 2009

%E a(12) and beyond from _Michael S. Branicky_, Aug 03 2022