Original entry on oeis.org
11, 131, 2, 929, 10301, 16361, 10281118201, 35605550653, 7159123219517
Offset: 1
A053600
a(1) = 2; for n>=1, a(n+1) is the smallest palindromic prime with a(n) as a central substring.
Original entry on oeis.org
2, 727, 37273, 333727333, 93337273339, 309333727333903, 1830933372733390381, 92183093337273339038129, 3921830933372733390381293, 1333921830933372733390381293331, 18133392183093337273339038129333181
Offset: 1
As a triangle:
.........2
........727
.......37273
.....333727333
....93337273339
..309333727333903
1830933372733390381
- G. L. Honaker, Jr. and Chris K. Caldwell, Palindromic Prime Pyramids, J. Recreational Mathematics, Vol. 30(3) 169-176, 1999-2000.
- Clark Kimberling, Table of n, a(n) for n = 1..200
- P. De Geest, Palindromic Prime Pyramid Puzzle by G.L.Honaker,Jr
- G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 18133...33181 (35-digits)
- G. L. Honaker, Jr. & C. K. Caldwell, Palindromic Prime Pyramids
- G. L. Honaker, Jr. & C. K. Caldwell, Supplement to "Palindromic Prime Pyramids"
- Ivars Peterson, Primes, Palindromes, and Pyramids, Science News.
- Inder J. Taneja, Palindromic Prime Embedded Trees, RGMIA Res. Rep. Coll. 20 (2017), Art. 124.
- Inder J. Taneja, Same Digits Embedded Palprimes, RGMIA Research Report Collection (2018) Vol. 21, Article 75, 1-47.
-
d[n_] := IntegerDigits[n]; t = {x = 2}; Do[i = 1; While[! PrimeQ[y = FromDigits[Flatten[{z = d[i], d[x], Reverse[z]}]]], i++]; AppendTo[t, x = y], {n, 10}]; t (* Jayanta Basu, Jun 24 2013 *)
-
from gmpy2 import digits, mpz, is_prime
A053600_list, p = [2], 2
for _ in range(30):
m, ps = 1, digits(p)
s = mpz('1'+ps+'1')
while not is_prime(s):
m += 1
ms = digits(m)
s = mpz(ms+ps+ms[::-1])
p = s
A053600_list.append(int(p)) # Chai Wah Wu, Apr 09 2015
A052205
a(n+1) is smallest palindromic prime containing exactly 3 more digits on each end than the previous term, with a(n) as a central substring.
Original entry on oeis.org
2, 1022201, 1051022201501, 1241051022201501421, 1071241051022201501421701, 1051071241051022201501421701501, 1091051071241051022201501421701501901, 1351091051071241051022201501421701501901531
Offset: 1
A034276
Smallest prime that generates a prime pyramid of height n.
Original entry on oeis.org
11, 29, 2, 5, 41, 251, 43, 145577, 51941, 4372877, 26901631, 366636187, 15387286403, 218761753811, 3313980408469
Offset: 1
Example for p=43: 43 3433 334333 93343339 3933433393 939334333939 39393343339393, stop; height(43)=7.
Showing 1-4 of 4 results.
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