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.
%I A182776 #7 Mar 30 2012 17:34:04 %S A182776 1,121,141,161,171,1241,1251,1261,1271,1281,1341,1351,1371,1391,1421, %T A182776 1431,1461,1491,1521,1541,1561,1581,1591,1631,1641,1651,1671,1681, %U A182776 1691,1731,1751,1761,1781,1791,1821,1841,1851,1891,1921,1941,1961,1971,1981,12321,12341,12351,12361,12371 %N A182776 Mountain nonprimes. %C A182776 The total number of terms is 19226. The largest is 12345678987654321 which is also the largest Giza number A134810. %F A182776 A018252 INTERSECT A134941. %e A182776 a(2)=121 is in the sequence because 121 is a nonprime number A018252 and 121 is also a mountain number A134941. %e A182776 Illustration of 134961 as a mountain nonprime: %e A182776 . . . 9 . . %e A182776 . . . . . . %e A182776 . . . . . . %e A182776 . . . . 6 . %e A182776 . . . . . . %e A182776 . . 4 . . . %e A182776 . 3 . . . . %e A182776 . . . . . . %e A182776 1 . . . . 1 %Y A182776 Cf. A018252, A134810, A134941, A134951. %K A182776 nonn,base,fini %O A182776 1,2 %A A182776 _Omar E. Pol_, Dec 14 2010