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A281020
Numbers with a prime number of raised dots in their Braille representation.
1
0, 1, 4, 6, 8, 12, 13, 15, 19, 21, 31, 47, 51, 67, 70, 74, 76, 78, 87, 91, 100, 104, 106, 108, 111, 127, 137, 140, 144, 146, 148, 157, 160, 164, 166, 168, 172, 173, 175, 177, 179, 180, 184, 186, 188, 197, 202, 203, 205, 207, 209, 217, 220, 224, 226, 228, 230, 234, 236, 238
OFFSET
1,3
LINKS
Indranil Ghosh, Braille Numerals
EXAMPLE
67 is in the sequence. 67, as evident from the link uploaded above, has 11 raised dots ("o") in its Braille representation and 11 is prime.
PROG
(Python)
from sympy import isprime
B=[3, 1, 2, 2, 3, 2, 3, 4, 3, 2]
def a(n):
s=0
for i in str(n):
s+=B[int(i)]
return s+4
i=0
j=1
while j<=10000:
if isprime(a(i))==True :
print str(j)+" "+str(i)
j+=1
i+=1
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Indranil Ghosh, Jan 13 2017
STATUS
approved