|
| |
|
|
A158862
|
|
Prepending 3 to n-th triangular number produces a prime.
|
|
1
| |
|
|
22, 46, 61, 82, 106, 118, 181, 286, 301, 373, 406, 433, 481, 493, 526, 562, 577, 661, 733, 802, 817, 886, 946, 961, 1033, 1162, 1177, 1246, 1258, 1261, 1297, 1342, 1426, 1513, 1546, 1558, 1573, 1618, 1741, 1813, 1822, 1846, 1873, 1882, 1918, 1921, 1957
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Or, concatenated T(2) and T(n) are prime. Or, concatenated A000217(2) and A000217(n) are prime.
|
|
|
EXAMPLE
| n=22: T(2)=253, 3253 is prime,
n=46: T(46)=1081, 31081 is prime,
n=61: T(61)=1891, 31891 is prime.
|
|
|
CROSSREFS
| A158844 Concatenated triangular numbers T (n), T(n + 1) and T(n + 2) are prime. A158845 Prepending 1 to n-th triangular number produces a prime. A158750 Concatenated triangular numbers that are prime. A000217 Triangular numbers.
Sequence in context: A041966 A106838 A190614 * A161666 A132763 A044099
Adjacent sequences: A158859 A158860 A158861 * A158863 A158864 A158865
|
|
|
KEYWORD
| base,nonn
|
|
|
AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Mar 28 2009
|
| |
|
|
