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. A070922.

Sequence in context: A159723 A282346 A070967 * A070922 A258586 A176940

Adjacent sequences: A070924 A070925 A070926 * A070928 A070929 A070930

easy,fini,full,nonn,base

Benoit Cloitre, May 24 2002

approved