A104182 Palindromes in the order in which they appear in Pascal's triangle, without repetition.

1, 2, 3, 4, 6, 5, 7, 8, 9, 252, 11, 55, 66, 1001, 2002, 3003, 5005, 8008, 171, 969, 22, 646646, 1771, 33, 595, 666, 3262623, 44, 77, 88, 99, 101, 5995, 111, 121, 131, 8778, 141, 151, 161, 15051, 181, 191, 202, 212, 222, 232, 242, 262, 272, 282, 292

Offset

1,2

Links

Table of n, a(n) for n=1..52.

Eric Weisstein's World of Mathematics, Pascal's Triangle

Example

Some rows of Pascal's Triangle:
Row 9 = {1, 9, 36, 84, 126, 126, 84, 36, 9, 1}
Row 10 = {1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1}
Row 1l = {1, 11, 55, 165, 330, 462, 462, 330, 165, 55, 11, 1}
Looking at this we see the palindromes of 9, 252, 11 and 55 in their order of appearance, without repetition.

Mathematica

DeleteDuplicates[Select[Flatten[Table[Binomial[n, m], {n, 0, 300}, {m, 0, n}]], IntegerDigits[#]==Reverse[IntegerDigits[#]]&]] (* Harvey P. Dale, May 04 2014 *)

Prog

(PARI) ispal(v) = {for(i=1, #v\2, if (v[i] != v[#v-i+1], return(0)); ); return(1); }; lista(n) = {ret = vector(0); for (i=1, n, for (j=1, i, numb = binomial(i, j); if (ispal(digits(numb)), if (! vecsearch(vecsort(ret), numb), ret = concat(ret, numb)); ); ); ); print(ret); } \\ Michel Marcus, Jun 08 2013

Crossrefs

Cf. A051641.

Sequence in context: A057164 A085175 A130111 * A371424 A371425 A361940

Adjacent sequences: A104179 A104180 A104181 * A104183 A104184 A104185

Keyword

nonn,base

Author

Andrew G. West (WestA(AT)wlu.edu), Mar 29 2005

Extensions

More terms from Michel Marcus, Jun 08 2013

Status

approved