A182776 Mountain nonprimes.

1, 121, 141, 161, 171, 1241, 1251, 1261, 1271, 1281, 1341, 1351, 1371, 1391, 1421, 1431, 1461, 1491, 1521, 1541, 1561, 1581, 1591, 1631, 1641, 1651, 1671, 1681, 1691, 1731, 1751, 1761, 1781, 1791, 1821, 1841, 1851, 1891, 1921, 1941, 1961, 1971, 1981, 12321, 12341, 12351, 12361, 12371

Offset

1,2

Comments

The total number of terms is 19226. The largest is 12345678987654321 which is also the largest Giza number A134810.

Links

Table of n, a(n) for n=1..48.

Formula

A018252 INTERSECT A134941.

Example

a(2)=121 is in the sequence because 121 is a nonprime number A018252 and 121 is also a mountain number A134941.
Illustration of 134961 as a mountain nonprime:
. . . 9 . .
. . . . . .
. . . . . .
. . . . 6 .
. . . . . .
. . 4 . . .
. 3 . . . .
. . . . . .
1 . . . . 1

Crossrefs

Cf. A018252, A134810, A134941, A134951.

Sequence in context: A050697 A319923 A020253 * A080466 A271630 A038511

Adjacent sequences: A182773 A182774 A182775 * A182777 A182778 A182779

Keyword

nonn,base,fini

Author

Omar E. Pol, Dec 14 2010

Status

approved