1,1

There are only 2 palindromic prime pyramids beginning with 2 (each one is finite with 5 elements).

G. L. Honaker Jr. and C. Caldwell, Palindromic prime pyramids, J. Recreational Mathematics, vol. 30.3, pp. 169-176, 1999-2000.

J.-P. Delahaye, "Pour la science", (French edition of Scientific American), Juin 2002, p. 99.

Table of n, a(n) for n=1..5.

Cf. A070927.

Sequence in context: A282346 A070967 A070927 * A258586 A176940 A172386

Adjacent sequences: A070919 A070920 A070921 * A070923 A070924 A070925

easy,fini,full,nonn,base

Benoit Cloitre, May 24 2002

approved