A226092 Fourth powers that become prime when their most significant (leftmost) decimal digit is removed.

2401, 279841, 15752961, 20151121, 35153041, 43046721, 62742241, 68574961, 88529281, 200533921, 260144641, 547981281, 671898241, 2385443281, 2655237841, 2750058481, 2847396321, 3262808641, 3722098081, 4640470641, 5887339441, 6414247921, 8428892481, 8882874001

Offset: 1

Author

Jonathan Vos Post, May 26 2013

Keywords

• nonn
• base
• easy

Comments

This is to fourth powers A000583 as A226090 is to as cubes A000578, and as A225873 is to squares A000290.

Examples

			a(1) = 7^4 = 2401, because removing the leftmost digit (4) leaves 401, which is prime.
a(2) = 23^4 = 279841, because removing the leftmost digit (2) leaves 79841, which is prime.
a(3) = 63^4 = 15752961, because removing the leftmost digit (1) leaves 5752961, which is prime.
a(10) = 119^4 = 200533921, because removing the leftmost digit (2) leaves 00533921 = 533921, which is prime.
		

Crossrefs

Cf. A000583, A225873, A226090.

Programs

Mathematica

Select[Range[307]^4, PrimeQ@Mod[#, 10^IntegerLength@#/10] &] (* Giovanni Resta, May 26 2013 *)

Extensions

a(13)-a(24) from Giovanni Resta, May 26 2013