A030146 Squares-of-primes in which no two adjacent digits have the same parity.

4, 9, 25, 49, 121, 169, 361, 529, 961, 12769, 16129, 18769, 32761, 72361, 76729, 78961, 96721, 212521, 214369, 436921, 452929, 458329, 1038361, 1630729, 1852321, 3892729, 5230369, 5470921, 5650129, 5812921, 5870929, 7230721

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Comments

Intersection of A030141 and A001248. - Michel Marcus, Feb 06 2015

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A030145, A030152.

Programs

Mathematica

Join[{4,9},Select[Prime[Range[4000]]^2,Union[Sort/@OddQ/@Partition[IntegerDigits[#],2,1]]=={{False,True}}&]] (* Harvey P. Dale, Feb 22 2011 *)

Formula

a(n) = A030145(n)^2. - Giovanni Resta, Aug 16 2018

Extensions

Definition clarified by Harvey P. Dale, Feb 23 2011

Offset changed by Michel Marcus, Feb 06 2015