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 A225048 Numbers that cannot be expressed as n plus the sum of the squared digits of n for any integer n. 2
 1, 3, 4, 5, 7, 8, 9, 10, 14, 15, 16, 18, 19, 21, 22, 25, 27, 28, 29, 32, 33, 34, 35, 37, 38, 40, 43, 46, 47, 48, 49, 50, 52, 55, 57, 60, 61, 63, 64, 65, 70, 71, 73, 74, 78, 79, 82, 84, 85, 88, 89, 91, 92, 93, 94, 97, 99, 100, 104, 106, 109, 110, 115, 120, 122 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A natural extension of the Self or Colombian numbers (A003052). Up to 144, there are more numbers that cannot be expressed in this way than numbers that can. Thereafter, there are always more numbers that can. LINKS Christian N. K. Anderson, Table of n, a(n) for n = 1..10000 EXAMPLE 26 is not in the sequence, because 21+2^2+1^2=26. However, no such solution exists for 25 or 27. MATHEMATICA nn=122; Complement[Range[nn], Table[n+Total[IntegerDigits[n]^2], {n, nn}]] (* Jayanta Basu, May 05 2013 *) PROG (R) digsqsum<-function(x) sum(as.numeric(unlist(strsplit(as.character(x), split="")))^2) which(is.na(match(1:1000, 1:1000+sapply(1:1000, digsqsum))) CROSSREFS Cf. A003052, A003219, A003132, A062028, A066568. Sequence in context: A241687 A169757 A051374 * A116590 A024355 A194413 Adjacent sequences:  A225045 A225046 A225047 * A225049 A225050 A225051 KEYWORD nonn,base AUTHOR Kevin L. Schwartz and Christian N. K. Anderson, Apr 25 2013 STATUS approved

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Last modified October 23 23:51 EDT 2019. Contains 328379 sequences. (Running on oeis4.)