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A028553 Numbers n such that n(n+3) is a palindrome. 2
0, 1, 8, 28, 66, 88, 211, 298, 671, 2126, 2998, 28814, 29369, 29998, 63701, 212206, 212671, 299998, 636776, 2122206, 2861419, 2999998, 9443423, 21341691, 28862883, 29999998, 212325206, 289053683, 294127328, 294174669, 299999998 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Also: sum of the first n even composites is palindromic. Sequence is 4 + 6 + 8 + 10 + 12 + 14 + ... + z. For values of z see A058851. (Comment added by author 12/2000).

LINKS

Table of n, a(n) for n=1..31.

P. De Geest, Palindromic Quasipronics

P. De Geest, Palindromic Sums 2

Erich Friedman, What's Special About This Number? (See entries 298, 2126, 2998.)

CROSSREFS

Cf. A058852, A028554.

Sequence in context: A007259 A134747 A083013 * A100182 A119515 A153976

Adjacent sequences:  A028550 A028551 A028552 * A028554 A028555 A028556

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified January 22 22:38 EST 2018. Contains 298093 sequences.