A028349 Palindromes of form n^2 + 3*n + 1.

1, 5, 11, 55, 131, 181, 505, 929, 1331, 9119, 10301, 14041, 15251, 106601, 145541, 196691, 1003001, 1284821, 1712171, 9452549, 100030001, 106636601, 112434211, 160111061, 174464471, 924494429, 950828059, 990707099, 1067557601, 9140220419, 9300770039

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..49

P. De Geest, Palindromic Quasi_Under_Squares of the form n+(n+1)^2

Mathematica

PalindromeQ = ((# // IntegerDigits // Reverse // FromDigits) == #) &; Select[Table[n^2 + 3*n + 1, {n, 1, 5000}], PalindromeQ] (* G. C. Greubel, Nov 26 2016 *)

Prog

(Magma) [p: n in [0..100000] | s eq Reverse(s) where s is Intseq(p) where p is n^2+3*n+1]; // Vincenzo Librandi, Nov 26 2016

Crossrefs

Cf. A028348.

Sequence in context: A104065 A212304 A018545 * A149528 A149529 A149530

Adjacent sequences: A028346 A028347 A028348 * A028350 A028351 A028352

Keyword

nonn,base

Author

Patrick De Geest

Extensions

Name corrected and sequence extended by T. D. Noe, Apr 17 2012

Status

approved