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A264725 Numbers n such that the concatenation of the first n digits of the digital expansion of 1/137 is prime. 0
3, 11, 371, 1123, 8203, 11899, 16019 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No further terms through 5000.

a(n) == 3 mod 8 for all n. If m <> 3 mod 8, then the concatenation of the first m digits is either even or a multiple of 3. - Chai Wah Wu, Nov 24 2015

REFERENCES

Clifford A. Pickover, A Passion for Mathematics, John Wiley & Sons, Inc., 2005, p. 88.

LINKS

Table of n, a(n) for n=1..7.

MATHEMATICA

Select[Range[2000], PrimeQ[FromDigits[PadRight[{}, #, {0, 0, 7, 2, 9, 9, 2, 7}]]]&]

PROG

(Python)

from sympy import isprime

A264725_list, c, n, m, k = [], 3, 7, 29927007, 10**8

for i in range(1, 50):

if isprime(n):

A264725_list.append(c)

c += 8

n = n*k+m # Chai Wah Wu, Nov 24 2015

CROSSREFS

Sequence in context: A097423 A111130 A337415 * A088579 A344946 A006938

Adjacent sequences: A264722 A264723 A264724 * A264726 A264727 A264728

KEYWORD

nonn,base,more

AUTHOR

Harvey P. Dale, Nov 22 2015

EXTENSIONS

a(5)-a(7) from Chai Wah Wu, Nov 24 2015

STATUS

approved

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Last modified December 3 15:03 EST 2022. Contains 358534 sequences. (Running on oeis4.)