A110778 -id:A110778 - cp's OEIS frontend

A110789 Number of digits in A110788(n).

1, 1, 2, 4, 5, 10, 23, 102, 102, 138, 451, 1922, 1624, 5630, 26410

Offset: 1

Amarnath Murthy, Aug 13 2005

Cf. A110774, A110775, A110776, A110777, A110778, A110780, A110781, A110782, A110783, A110788.

from sympy import isprime
from itertools import count, islice
def agen(): # generator of terms
    s = ""
    while True:
        for d in "71":
            for k in count(1):
                if isprime(int(s+d*k)): break
            yield k
            s += d*k
print(list(islice(agen(), 11))) # Michael S. Branicky, Aug 23 2022

More terms from Joshua Zucker, Jan 11 2006
a(12) from Sean A. Irvine, Mar 22 2010
a(13)-a(14) from Michael S. Branicky, Aug 23 2022
a(15) from Michael S. Branicky, Nov 20 2024

A110790 Copies of 3 and 1 alternately such that every partial concatenation is a prime.

Original entry on oeis.org

3, 1, 3, 111111111111111, 33333, 111111111111111111111111111111111111111111111111111111111111111111111111111111111111111, 3333, 111111111111111111111111111, 33333

Offset: 1

Amarnath Murthy, Aug 13 2005

The next term has 168 digits. - Charles R Greathouse IV, Sep 29 2008

			3, 31, 313, 313111111111111111, ... are all prime.

Cf. A110791 (digit lengths)

Other digits: A110774, A110776, A110778, A110780, A110782, A110788.

a(6)-a(9) from_Charles R Greathouse IV_, Sep 29 2008

A110791 Number of digits in A110790(n).

Original entry on oeis.org

1, 1, 1, 15, 5, 87, 4, 27, 5, 168, 27, 478, 70

Offset: 1

Amarnath Murthy, Aug 13 2005

Next term is >= 478. [From David Wasserman, Jan 06 2009]

			3, 31, 313, 313111111111111111, ... are all prime.

Cf. A110774, A110775, A110776, A110777, A110778, A110780, A110781, A110782, A110783, A110788, A110789, A110790.

More terms from David Wasserman, Jan 06 2009

Two more terms from Sean A. Irvine, Mar 22 2010

A110792 Copies of 7,3 and 1 cyclically such that every partial concatenation is a prime.

Original entry on oeis.org

7, 3, 1111111, 777777777, 33, 11111111111111111111111111111111111111111111111111111111111111111, 7777777777777777777, 33333333333333333333, 111111111111111111111111111111111111111

Offset: 1

Amarnath Murthy, Aug 13 2005

			7,73,731111111,...are all prime.

Cf. A110793 (digit lengths).

Other combinations: A110774, A110776, A110778, A110780, A110782, A110788, A110790.

More terms from Sean A. Irvine, Mar 21 2010

a(9) from Jon E. Schoenfield, Jul 11 2010

A110793 Number of digits in A110792(n).

Original entry on oeis.org

1, 1, 7, 9, 2, 65, 19, 20, 39, 54, 228, 231, 149, 630, 1641, 8794, 12907

Offset: 1

Amarnath Murthy, Aug 13 2005

Cf. A110774, A110775, A110776, A110777, A110778, A110780, A110781, A110782, A110783, A110788, A110789, A110790, A110791, A110792.

a(6)-a(15) from Sean A. Irvine, Mar 22 2010
a(16) from Michael S. Branicky, Jun 23 2023
a(17) from Michael S. Branicky, Nov 19 2024

cp's OEIS Frontend

A110789 Number of digits in A110788(n).

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A110790 Copies of 3 and 1 alternately such that every partial concatenation is a prime.

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A110791 Number of digits in A110790(n).

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A110792 Copies of 7,3 and 1 cyclically such that every partial concatenation is a prime.

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A110793 Number of digits in A110792(n).

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