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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..10000

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

Cf. A072283, A281015, A281017.

Sequence in context: A031359 A274790 A179852 * A110606 A241124 A117247

Adjacent sequences:  A281017 A281018 A281019 * A281021 A281022 A281023

KEYWORD

nonn,base

AUTHOR

Indranil Ghosh, Jan 13 2017

STATUS

approved

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Last modified February 28 08:22 EST 2020. Contains 332322 sequences. (Running on oeis4.)