A066751 Triangular numbers whose reverse is prime.

3, 91, 136, 325, 703, 1081, 1378, 1711, 3655, 11026, 11476, 13861, 18145, 18721, 36046, 70876, 75466, 76636, 79003, 92665, 99235, 107416, 108811, 110215, 118828, 123256, 130816, 137026, 140185, 158203, 166753, 173755, 186355, 303031, 310078

Offset

1,1

Comments

Numbers ending in 0 are not included.

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harry J. Smith)

Mathematica

Select[PolygonalNumber[Range[1000]], Mod[#, 10] > 0 && PrimeQ[IntegerReverse[#]] &] (* Paolo Xausa, Jan 18 2026 *)

Prog

(PARI)
Rev(x)= { local(d, r=0); while (x>0, d=x%10; x\=10; r=r*10 + d); return(r) }
{ n=0; for (m=1, 10^10, t=m*(m + 1)/2; if (t%10 && isprime(Rev(t)), write("b066751.txt", n++, " ", t); if (n==1000, return)) ) } \\ Harry J. Smith, Mar 21 2010

Crossrefs

Cf. A000040, A000217, A004086, A066569.

Sequence in context: A339580 A374392 A115704 * A115886 A041439 A366219

Adjacent sequences: A066748 A066749 A066750 * A066752 A066753 A066754

Keyword

easy,nonn,base

Author

Jason Earls, Jan 16 2002

Status

approved