This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
def A195269(n): m, s = 1, '0'*n for i in range(1,10**9): m *= 3 if s in str(m): return i return "search limit reached." # Chai Wah Wu, Dec 11 2014
a(3)=35 because 3^35 (i.e., 50031545098999707) is the smallest power of 3 to contain a run of 3 consecutive nines in its decimal form.
a = ""; Do[ a = StringJoin[a, "9"]; b = StringJoin[a, "9"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
def A131544(n): m, s = 1, '9'*n for i in range(1,10**9): m *= 3 if s in str(m): return i return "search limit reached." # Chai Wah Wu, Dec 11 2014
a(3)=93 because 3^93 (i.e., 235655016338368235499067731945871638181119123) is the smallest power of 3 to contain a run of 3 consecutive ones in its decimal form.
a = ""; Do[ a = StringJoin[a, "1"]; b = StringJoin[a, "1"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
def A131552(n): m, s = 1, '1'*n for i in range(1, 10**9): m *= 3 if s in str(m): return i return "search limit reached." # Chai Wah Wu, Dec 11 2014
a(3)=32 because 3^32 (i.e., 1853020188851841) is the smallest power of 3 to contain a run of 3 consecutive eights in its decimal form.
a = ""; Do[ a = StringJoin[a, "8"]; b = StringJoin[a, "8"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
a(3)=34 because 3^34(i.e. 16677181699666569) is the smallest power of 3 to contain a run of 3 consecutive sixes in its decimal form.
a = ""; Do[ a = StringJoin[a, "6"]; b = StringJoin[a, "6"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
a(3) = 33 because 3^33 = 5559060566555523 is the smallest power of 3 that contains a run of exactly 3 consecutive 5's in its decimal form. (3^33 happens to contain also a run of exactly 4 consecutive 5's, so a(4) is also 33.)
a(3)=55 because 3^55 (i.e., 174449211009120179071170507) is the smallest power of 3 to contain a run of 3 consecutive fours in its decimal form.
a = ""; Do[ a = StringJoin[a, "4"]; b = StringJoin[a, "4"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
def a(n):
target, antitarget = '4'*n, '4'*(n+1)
k, pow3 = 1, 3
while True:
t = str(pow3)
if target in t and antitarget not in t: return k
k, pow3 = k+1, pow3*3
print([a(n) for n in range(1, 9)]) # Michael S. Branicky, May 12 2021
a(3)=119 because 3^119 (i.e., 599003433304810403471059943169868346577158542512617035467) is the smallest power of 3 to contain a run of 3 consecutive threes in its decimal form.
a = ""; Do[ a = StringJoin[a, "3"]; b = StringJoin[a, "3"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
a(3)=148 because 3^148 (i.e. 41109831670569663658300086939077404909608122265524774868353822811305361) is the smallest power of 3 to contain a run of 3 consecutive twos in its decimal form.
a = ""; Do[ a = StringJoin[a, "2"]; b = StringJoin[a, "2"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
def a(n):
k, n2, np2 = 1, '2'*n, '2'*(n+1)
while True:
while not n2 in str(3**k): k += 1
if np2 not in str(3**k): return k
k += 1
print([a(n) for n in range(1, 8)]) # Michael S. Branicky, Mar 19 2021
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