A115705 Primes whose digit reversal is a triangular number.

3, 19, 307, 523, 631, 1171, 1801, 5563, 8731, 12781, 16831, 30097, 53299, 54181, 56629, 62011, 63667, 64063, 66457, 67411, 67807, 108127, 118801, 128413, 130303, 131059, 160453, 188677, 192637, 196597, 300583, 302851, 357661

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..400

Example

307 is prime and 703=T(73).

Mathematica

Select[Prime[Range[20000]], OddQ[Sqrt[1+8IntegerReverse[#]]]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 01 2019 *)

Crossrefs

Cf. A115704.

Sequence in context: A356512 A143597 A224681 * A136171 A102586 A326902

Adjacent sequences: A115702 A115703 A115704 * A115706 A115707 A115708

Keyword

nonn,base

Author

Giovanni Resta, Jan 31 2006

Status

approved